From 608aadeed059792f4f553b602ffbb1af90df2f9f Mon Sep 17 00:00:00 2001
From: Julien Gacon <gaconju@gmail.com>
Date: Tue, 27 Oct 2020 16:13:45 +0100
Subject: [PATCH] move to circuit.lib and use tuple

- move the initial state circuit to chemistry.circuit.library
- globally replace num_particles by a tuple instead of list of integers
---
 README.md                                     |   7 +-
 .../legacy/weighted_pauli_operator.py         |   2 +-
 .../vqe_uccsd_factory.py                      |   2 +-
 .../molecular_ground_state_energy.py          |   2 +-
 qiskit/chemistry/circuit/library/__init__.py  |  39 ++++++
 .../library/initial_states/__init__.py        |  18 +++
 .../library/initial_states/hartree_fock.py    | 116 ++++++++++++++++++
 .../circuit/library/initial_states/vscf.py    |  60 +++++++++
 .../components/initial_states/hartree_fock.py |  88 ++-----------
 .../components/initial_states/vscf.py         |  42 ++-----
 .../components/variational_forms/uccsd.py     |   8 +-
 qiskit/chemistry/core/hamiltonian.py          |  14 +--
 .../fermionic_transformation.py               |  14 +--
 .../circuit/library/test_hartree_fock.py      |  62 ++++++++++
 test/chemistry/circuit/library/test_vscf.py   |  44 +++++++
 test/chemistry/test_adapt_vqe.py              |   2 +-
 test/chemistry/test_app_mgse.py               |   2 +-
 test/chemistry/test_bopes_sampler.py          |   5 +-
 test/chemistry/test_chc_vscf.py               |   5 +-
 test/chemistry/test_core_hamiltonian.py       |   2 +-
 .../test_core_hamiltonian_orb_reduce.py       |  10 +-
 test/chemistry/test_end2end_with_iqpe.py      |   2 +-
 test/chemistry/test_end2end_with_qpe.py       |   2 +-
 .../test_fermionic_transformation.py          |   2 +-
 ...est_fermionic_transformation_orb_reduce.py |  10 +-
 .../test_initial_state_hartree_fock.py        |  41 -------
 test/chemistry/test_initial_state_vscf.py     |  25 +---
 test/chemistry/test_qeom_vqe.py               |   2 +-
 test/chemistry/test_readme_sample.py          |   7 +-
 test/chemistry/test_swaprz.py                 |   5 +-
 test/chemistry/test_symmetries.py             |   2 +-
 test/chemistry/test_uccsd_advanced.py         |   2 +-
 test/chemistry/test_uccsd_hartree_fock.py     |   5 +-
 test/chemistry/test_uvcc_vscf.py              |   5 +-
 test/chemistry/test_vqe_uccsd_adapt.py        |   2 +-
 35 files changed, 431 insertions(+), 225 deletions(-)
 create mode 100644 qiskit/chemistry/circuit/library/__init__.py
 create mode 100644 qiskit/chemistry/circuit/library/initial_states/__init__.py
 create mode 100644 qiskit/chemistry/circuit/library/initial_states/hartree_fock.py
 create mode 100644 qiskit/chemistry/circuit/library/initial_states/vscf.py
 create mode 100644 test/chemistry/circuit/library/test_hartree_fock.py
 create mode 100644 test/chemistry/circuit/library/test_vscf.py

diff --git a/README.md b/README.md
index 12df2a29a7..5c9275036c 100644
--- a/README.md
+++ b/README.md
@@ -223,12 +223,15 @@ from qiskit.aqua.components.optimizers import L_BFGS_B
 optimizer = L_BFGS_B()
 
 # setup the initial state for the variational form
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 init_state = HartreeFock(num_spin_orbitals, num_particles)
 
 # setup the variational form for VQE
 from qiskit.circuit.library import TwoLocal
-var_form = TwoLocal(num_qubits, ['ry', 'rz'], 'cz', initial_state=init_state)
+var_form = TwoLocal(num_qubits, ['ry', 'rz'], 'cz')
+
+# add the initial state
+var_form.compose(init_state, front=True)
 
 # setup and run VQE
 from qiskit.aqua.algorithms import VQE
diff --git a/qiskit/aqua/operators/legacy/weighted_pauli_operator.py b/qiskit/aqua/operators/legacy/weighted_pauli_operator.py
index 0893cbf863..4f1ab27649 100644
--- a/qiskit/aqua/operators/legacy/weighted_pauli_operator.py
+++ b/qiskit/aqua/operators/legacy/weighted_pauli_operator.py
@@ -1250,7 +1250,7 @@ def two_qubit_reduction(operator, num_particles):
                         "Return the empty operator back.")
             return operator
 
-        if isinstance(num_particles, list):
+        if isinstance(num_particles, (tuple, list)):
             num_alpha = num_particles[0]
             num_beta = num_particles[1]
         else:
diff --git a/qiskit/chemistry/algorithms/ground_state_solvers/minimum_eigensolver_factories/vqe_uccsd_factory.py b/qiskit/chemistry/algorithms/ground_state_solvers/minimum_eigensolver_factories/vqe_uccsd_factory.py
index c1623f6d4c..eb430d20e3 100644
--- a/qiskit/chemistry/algorithms/ground_state_solvers/minimum_eigensolver_factories/vqe_uccsd_factory.py
+++ b/qiskit/chemistry/algorithms/ground_state_solvers/minimum_eigensolver_factories/vqe_uccsd_factory.py
@@ -22,7 +22,7 @@
 from ....components.variational_forms import UCCSD
 from ....transformations import Transformation
 from ....transformations.fermionic_transformation import FermionicTransformation
-from ....components.initial_states import HartreeFock
+from ....circuit.library import HartreeFock
 
 from .minimum_eigensolver_factory import MinimumEigensolverFactory
 
diff --git a/qiskit/chemistry/applications/molecular_ground_state_energy.py b/qiskit/chemistry/applications/molecular_ground_state_energy.py
index eecec094e5..63521f284b 100644
--- a/qiskit/chemistry/applications/molecular_ground_state_energy.py
+++ b/qiskit/chemistry/applications/molecular_ground_state_energy.py
@@ -21,7 +21,7 @@
 from qiskit.aqua.algorithms import MinimumEigensolver, VQE
 from qiskit.aqua.operators import Z2Symmetries
 from qiskit.chemistry import QiskitChemistryError
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.chemistry.components.variational_forms import UCCSD
 from qiskit.chemistry.core import (Hamiltonian, TransformationType, QubitMappingType,
                                    ChemistryOperator, MolecularGroundStateResult)
diff --git a/qiskit/chemistry/circuit/library/__init__.py b/qiskit/chemistry/circuit/library/__init__.py
new file mode 100644
index 0000000000..036a8bee87
--- /dev/null
+++ b/qiskit/chemistry/circuit/library/__init__.py
@@ -0,0 +1,39 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""
+===================================================================
+Chemistry Circuit Library (:mod:`qiskit.chemistry.circuit.library`)
+===================================================================
+
+A collection of circuits used as building blocks or inputs of algorithms in chemistry.
+
+.. currentmodule:: qiskit.chemistry.circuit.library
+
+Initial states
+==============
+
+.. autosummary::
+   :toctree: ../stubs/
+   :nosignatures:
+
+   HartreeFock
+   VSCF
+
+"""
+
+from .initial_states import (
+    HartreeFock,
+    VSCF
+)
+
+__all__ = ['HartreeFock', 'VSCF']
diff --git a/qiskit/chemistry/circuit/library/initial_states/__init__.py b/qiskit/chemistry/circuit/library/initial_states/__init__.py
new file mode 100644
index 0000000000..82b47043a6
--- /dev/null
+++ b/qiskit/chemistry/circuit/library/initial_states/__init__.py
@@ -0,0 +1,18 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Initial state circuits."""
+
+from .hartree_fock import HartreeFock
+from .vscf import VSCF
+
+__all__ = ['HartreeFock', 'VSCF']
diff --git a/qiskit/chemistry/circuit/library/initial_states/hartree_fock.py b/qiskit/chemistry/circuit/library/initial_states/hartree_fock.py
new file mode 100644
index 0000000000..c279a0f089
--- /dev/null
+++ b/qiskit/chemistry/circuit/library/initial_states/hartree_fock.py
@@ -0,0 +1,116 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2018, 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Hartree-Fock initial state."""
+
+import warnings
+from typing import Optional, Union, List, Tuple
+import logging
+import numpy as np
+from qiskit import QuantumRegister, QuantumCircuit
+from qiskit.aqua.utils.validation import validate_min, validate_in_set
+
+logger = logging.getLogger(__name__)
+
+
+class HartreeFock(QuantumCircuit):
+    """A Hartree-Fock initial state."""
+
+    def __init__(self,
+                 num_orbitals: int,
+                 num_particles: Union[Tuple[int, int], int],
+                 qubit_mapping: str = 'parity',
+                 two_qubit_reduction: bool = True,
+                 sq_list: Optional[List[int]] = None) -> None:
+        """
+        Args:
+            num_orbitals: number of spin orbitals, has a min. value of 1.
+            num_particles: number of particles, if it is a list, the first number
+                            is alpha and the second number if beta.
+            qubit_mapping: mapping type for qubit operator
+            two_qubit_reduction: flag indicating whether or not two qubit is reduced
+            sq_list: position of the single-qubit operators that
+                    anticommute with the cliffords
+
+        Raises:
+            ValueError: wrong setting in num_particles and num_orbitals.
+            ValueError: wrong setting for computed num_qubits and supplied num_qubits.
+        """
+        # validate the input
+        validate_min('num_orbitals', num_orbitals, 1)
+        validate_in_set('qubit_mapping', qubit_mapping,
+                        {'jordan_wigner', 'parity', 'bravyi_kitaev'})
+
+        if qubit_mapping != 'parity' and two_qubit_reduction:
+            warnings.warn('two_qubit_reduction only works with parity qubit mapping '
+                          'but you have %s. We switch two_qubit_reduction '
+                          'to False.' % qubit_mapping)
+            two_qubit_reduction = False
+
+        # get the bitstring encoding the Hartree Fock state
+        bitstr = _build_bitstr(num_orbitals, num_particles, qubit_mapping,
+                               two_qubit_reduction, sq_list)
+
+        # construct the circuit
+        qr = QuantumRegister(len(bitstr), 'q')
+        super().__init__(qr, name='HF')
+
+        # add gates in the right positions
+        for i, bit in enumerate(reversed(bitstr)):
+            if bit:
+                self.x(i)
+
+
+def _build_bitstr(num_orbitals, num_particles, qubit_mapping, two_qubit_reduction=True,
+                  sq_list=None):
+    if isinstance(num_particles, tuple):
+        num_alpha, num_beta = num_particles
+    else:
+        logger.info('We assume that the number of alphas and betas are the same.')
+        num_alpha = num_beta = num_particles // 2
+
+    num_particles = num_alpha + num_beta
+
+    if num_particles > num_orbitals:
+        raise ValueError('# of particles must be less than or equal to # of orbitals.')
+
+    half_orbitals = num_orbitals // 2
+    bitstr = np.zeros(num_orbitals, np.bool)
+    bitstr[-num_alpha:] = True
+    bitstr[-(half_orbitals + num_beta):-half_orbitals] = True
+
+    if qubit_mapping == 'parity':
+        new_bitstr = bitstr.copy()
+
+        t_r = np.triu(np.ones((num_orbitals, num_orbitals)))
+        new_bitstr = t_r.dot(new_bitstr.astype(np.int)) % 2  # pylint: disable=no-member
+
+        bitstr = np.append(new_bitstr[1:half_orbitals], new_bitstr[half_orbitals + 1:]) \
+            if two_qubit_reduction else new_bitstr
+
+    elif qubit_mapping == 'bravyi_kitaev':
+        binary_superset_size = int(np.ceil(np.log2(num_orbitals)))
+        beta = 1
+        basis = np.asarray([[1, 0], [0, 1]])
+        for _ in range(binary_superset_size):
+            beta = np.kron(basis, beta)
+            beta[0, :] = 1
+        start_idx = beta.shape[0] - num_orbitals
+        beta = beta[start_idx:, start_idx:]
+        new_bitstr = beta.dot(bitstr.astype(int)) % 2
+        bitstr = new_bitstr.astype(np.bool)
+
+    if sq_list is not None:
+        sq_list = [len(bitstr) - 1 - position for position in sq_list]
+        bitstr = np.delete(bitstr, sq_list)
+
+    return bitstr.astype(np.bool)
diff --git a/qiskit/chemistry/circuit/library/initial_states/vscf.py b/qiskit/chemistry/circuit/library/initial_states/vscf.py
new file mode 100644
index 0000000000..8a877e6edc
--- /dev/null
+++ b/qiskit/chemistry/circuit/library/initial_states/vscf.py
@@ -0,0 +1,60 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Initial state for vibrational modes."""
+
+from typing import List
+
+import numpy as np
+
+from qiskit import QuantumRegister, QuantumCircuit
+
+
+class VSCF(QuantumCircuit):
+    r"""Initial state for vibrational modes.
+
+    Creates an occupation number vector as defined in [1].
+    As example, for 2 modes with 4 modals per mode it creates: :math:`|1000 1000\rangle`.
+
+    References:
+
+        [1] Ollitrault Pauline J., Chemical science 11 (2020): 6842-6855.
+    """
+
+    def __init__(self, basis: List[int]) -> None:
+        """
+        Args:
+            basis: Is a list defining the number of modals per mode. E.g. for a 3 modes system
+                with 4 modals per mode basis = [4,4,4]
+        """
+        # get the bitstring encoding initial state
+        bitstr = _build_bitstr(basis)
+
+        # construct the circuit
+        qr = QuantumRegister(len(bitstr), 'q')
+        super().__init__(qr, name='VSCF')
+
+        # add gates in the right positions
+        for i, bit in enumerate(reversed(bitstr)):
+            if bit:
+                self.x(i)
+
+
+def _build_bitstr(basis):
+    num_qubits = sum(basis)
+    bitstr = np.zeros(num_qubits, np.bool)
+    count = 0
+    for modal in basis:
+        bitstr[num_qubits - count - 1] = True
+        count += modal
+
+    return bitstr
diff --git a/qiskit/chemistry/components/initial_states/hartree_fock.py b/qiskit/chemistry/components/initial_states/hartree_fock.py
index 63ab43b498..74579f0e00 100644
--- a/qiskit/chemistry/components/initial_states/hartree_fock.py
+++ b/qiskit/chemistry/components/initial_states/hartree_fock.py
@@ -13,22 +13,23 @@
 """Hartree-Fock initial state."""
 
 import warnings
-from typing import Optional, Union, List, Tuple
+from typing import Optional, Union, List
 import logging
 import numpy as np
 from qiskit import QuantumRegister, QuantumCircuit
 from qiskit.aqua.utils.validation import validate_min, validate_in_set
 from qiskit.aqua.components.initial_states import InitialState
+from qiskit.chemistry.circuit.library.initial_states.hartree_fock import _build_bitstr
 
 logger = logging.getLogger(__name__)
 
 
-class HartreeFock(QuantumCircuit, InitialState):
+class HartreeFock(InitialState):
     """A Hartree-Fock initial state."""
 
     def __init__(self,
                  num_orbitals: int,
-                 num_particles: Union[Tuple[int, int], List[int], int],
+                 num_particles: Union[List[int], int],
                  qubit_mapping: str = 'parity',
                  two_qubit_reduction: bool = True,
                  sq_list: Optional[List[int]] = None) -> None:
@@ -57,27 +58,16 @@ def __init__(self,
                           'to False.' % qubit_mapping)
             two_qubit_reduction = False
 
-        if isinstance(num_particles, list):
-            warnings.warn('The ``num_particles`` argument should either be a single integer or a '
-                          'tuple of two integers, not a list. This behavious is deprecated as of '
-                          'Aqua 0.9 and will be removed no earlier than 3 months after the '
-                          'release.', DeprecationWarning, stacklevel=2)
-            num_particles = tuple(num_particles)  # type: ignore
+        super().__init__()
 
         # get the bitstring encoding the Hartree Fock state
+        if isinstance(num_particles, list):
+            num_particles = tuple(num_particles)
+
         bitstr = _build_bitstr(num_orbitals, num_particles, qubit_mapping,
                                two_qubit_reduction, sq_list)
         self._bitstr = bitstr
 
-        # construct the circuit
-        qr = QuantumRegister(len(bitstr), 'q')
-        super().__init__(qr, name='HF')
-
-        # add gates in the right positions
-        for i, bit in enumerate(reversed(bitstr)):
-            if bit:
-                self.x(i)
-
     def construct_circuit(self, mode='circuit', register=None):
         """Construct the statevector of desired initial state.
 
@@ -93,10 +83,6 @@ def construct_circuit(self, mode='circuit', register=None):
         Raises:
             ValueError: when mode is not 'vector' or 'circuit'.
         """
-        warnings.warn('The HartreeFock.construct_circuit method is deprecated as of Aqua 0.9.0 and '
-                      'will be removed no earlier than 3 months after the release. The HarteeFock '
-                      'class is now a QuantumCircuit instance and can directly be used as such.',
-                      DeprecationWarning, stacklevel=2)
         if mode == 'vector':
             state = 1.0
             one = np.asarray([0.0, 1.0])
@@ -106,9 +92,11 @@ def construct_circuit(self, mode='circuit', register=None):
             return state
         elif mode == 'circuit':
             if register is None:
-                register = QuantumRegister(self.num_qubits, name='q')
-            quantum_circuit = QuantumCircuit(register)
-            quantum_circuit.compose(self, inplace=True)
+                register = QuantumRegister(len(self.bitstr), name='q')
+            quantum_circuit = QuantumCircuit(register, name='HF')
+            for i, bit in enumerate(reversed(self.bitstr)):
+                if bit:
+                    quantum_circuit.x(i)
             return quantum_circuit
         else:
             raise ValueError('Mode should be either "vector" or "circuit"')
@@ -116,54 +104,4 @@ def construct_circuit(self, mode='circuit', register=None):
     @property
     def bitstr(self):
         """Getter of the bit string represented the statevector."""
-        warnings.warn('The HartreeFock.bitstr property is deprecated as of Aqua 0.9.0 and will be '
-                      'removed no earlier than 3 months after the release. To get the bitstring '
-                      'you can use the quantum_info.Statevector class and the probabilities_dict '
-                      'method.', DeprecationWarning, stacklevel=2)
         return self._bitstr
-
-
-def _build_bitstr(num_orbitals, num_particles, qubit_mapping, two_qubit_reduction=True,
-                  sq_list=None):
-    if isinstance(num_particles, tuple):
-        num_alpha, num_beta = num_particles
-    else:
-        logger.info('We assume that the number of alphas and betas are the same.')
-        num_alpha = num_beta = num_particles // 2
-
-    num_particles = num_alpha + num_beta
-
-    if num_particles > num_orbitals:
-        raise ValueError('# of particles must be less than or equal to # of orbitals.')
-
-    half_orbitals = num_orbitals // 2
-    bitstr = np.zeros(num_orbitals, np.bool)
-    bitstr[-num_alpha:] = True
-    bitstr[-(half_orbitals + num_beta):-half_orbitals] = True
-
-    if qubit_mapping == 'parity':
-        new_bitstr = bitstr.copy()
-
-        t_r = np.triu(np.ones((num_orbitals, num_orbitals)))
-        new_bitstr = t_r.dot(new_bitstr.astype(np.int)) % 2  # pylint: disable=no-member
-
-        bitstr = np.append(new_bitstr[1:half_orbitals], new_bitstr[half_orbitals + 1:]) \
-            if two_qubit_reduction else new_bitstr
-
-    elif qubit_mapping == 'bravyi_kitaev':
-        binary_superset_size = int(np.ceil(np.log2(num_orbitals)))
-        beta = 1
-        basis = np.asarray([[1, 0], [0, 1]])
-        for _ in range(binary_superset_size):
-            beta = np.kron(basis, beta)
-            beta[0, :] = 1
-        start_idx = beta.shape[0] - num_orbitals
-        beta = beta[start_idx:, start_idx:]
-        new_bitstr = beta.dot(bitstr.astype(int)) % 2
-        bitstr = new_bitstr.astype(np.bool)
-
-    if sq_list is not None:
-        sq_list = [len(bitstr) - 1 - position for position in sq_list]
-        bitstr = np.delete(bitstr, sq_list)
-
-    return bitstr.astype(np.bool)
diff --git a/qiskit/chemistry/components/initial_states/vscf.py b/qiskit/chemistry/components/initial_states/vscf.py
index 5893ed81dd..8a0b73b5ad 100644
--- a/qiskit/chemistry/components/initial_states/vscf.py
+++ b/qiskit/chemistry/components/initial_states/vscf.py
@@ -13,7 +13,6 @@
 """ Initial state for vibrational modes. """
 
 import logging
-import warnings
 from typing import List
 
 import numpy as np
@@ -21,10 +20,12 @@
 from qiskit import QuantumRegister, QuantumCircuit
 from qiskit.aqua.components.initial_states import InitialState
 
+from qiskit.chemistry.circuit.library.initial_states.vscf import _build_bitstr
+
 logger = logging.getLogger(__name__)
 
 
-class VSCF(QuantumCircuit, InitialState):
+class VSCF(InitialState):
     r"""Initial state for vibrational modes.
 
     Creates an occupation number vector as defined in
@@ -42,14 +43,7 @@ def __init__(self, basis: List[int]) -> None:
         bitstr = _build_bitstr(basis)
         self._bitstr = bitstr
 
-        # construct the circuit
-        qr = QuantumRegister(len(bitstr), 'q')
-        super().__init__(qr, name='VSCF')
-
-        # add gates in the right positions
-        for i, bit in enumerate(reversed(bitstr)):
-            if bit:
-                self.x(i)
+        super().__init__()
 
     def construct_circuit(self, mode='circuit', register=None):
         """Construct the statevector of desired initial state.
@@ -66,10 +60,6 @@ def construct_circuit(self, mode='circuit', register=None):
         Raises:
             ValueError: when mode is not 'vector' or 'circuit'.
         """
-        warnings.warn('The VSCF.construct_circuit method is deprecated as of Aqua 0.9.0 and '
-                      'will be removed no earlier than 3 months after the release. The HarteeFock '
-                      'class is now a QuantumCircuit instance and can directly be used as such.',
-                      DeprecationWarning, stacklevel=2)
         if mode == 'vector':
             state = 1.0
             one = np.asarray([0.0, 1.0])
@@ -79,9 +69,12 @@ def construct_circuit(self, mode='circuit', register=None):
             return state
         elif mode == 'circuit':
             if register is None:
-                register = QuantumRegister(self.num_qubits, name='q')
-            quantum_circuit = QuantumCircuit(register)
-            quantum_circuit.compose(self, inplace=True)
+                register = QuantumRegister(len(self.bitstr), name='q')
+            quantum_circuit = QuantumCircuit(register, name='VSCF')
+            for i, bit in enumerate(reversed(self.bitstr)):
+                if bit:
+                    quantum_circuit.x(i)
+
             return quantum_circuit
         else:
             raise ValueError('Mode should be either "vector" or "circuit"')
@@ -89,19 +82,4 @@ def construct_circuit(self, mode='circuit', register=None):
     @property
     def bitstr(self):
         """Getter of the bit string represented the statevector."""
-        warnings.warn('The VSCF.bitstr property is deprecated as of Aqua 0.9.0 and will be '
-                      'removed no earlier than 3 months after the release. To get the bitstring '
-                      'you can use the quantum_info.Statevector class and the probabilities_dict '
-                      'method.', DeprecationWarning, stacklevel=2)
         return self._bitstr
-
-
-def _build_bitstr(basis):
-    num_qubits = sum(basis)
-    bitstr = np.zeros(num_qubits, np.bool)
-    count = 0
-    for modal in basis:
-        bitstr[num_qubits - count - 1] = True
-        count += modal
-
-    return bitstr
diff --git a/qiskit/chemistry/components/variational_forms/uccsd.py b/qiskit/chemistry/components/variational_forms/uccsd.py
index db62590826..0ec88d8e08 100644
--- a/qiskit/chemistry/components/variational_forms/uccsd.py
+++ b/qiskit/chemistry/components/variational_forms/uccsd.py
@@ -17,7 +17,7 @@
 And for singlet q-UCCD (full) and pair q-UCCD see: https://arxiv.org/abs/1911.10864
 """
 
-from typing import Optional, Union, List
+from typing import Optional, Union, List, Tuple
 import logging
 import sys
 import collections
@@ -48,7 +48,7 @@ class UCCSD(VariationalForm):
 
     def __init__(self,
                  num_orbitals: int,
-                 num_particles: Union[List[int], int],
+                 num_particles: Union[Tuple[int, int], List[int], int],
                  reps: int = 1,
                  active_occupied: Optional[List[int]] = None,
                  active_unoccupied: Optional[List[int]] = None,
@@ -118,7 +118,7 @@ def __init__(self,
             else self._num_qubits - len(self._z2_symmetries.sq_list)
         self._reps = reps
         self._num_orbitals = num_orbitals
-        if isinstance(num_particles, list):
+        if isinstance(num_particles, (tuple, list)):
             self._num_alpha = num_particles[0]
             self._num_beta = num_particles[1]
         else:
@@ -490,7 +490,7 @@ def compute_excitation_lists(num_particles, num_orbitals, active_occ_list=None,
             ValueError: invalid setting of number of orbitals
         """
 
-        if isinstance(num_particles, list):
+        if isinstance(num_particles, (tuple, list)):
             num_alpha = num_particles[0]
             num_beta = num_particles[1]
         else:
diff --git a/qiskit/chemistry/core/hamiltonian.py b/qiskit/chemistry/core/hamiltonian.py
index 847be15fcb..9fe48891cd 100644
--- a/qiskit/chemistry/core/hamiltonian.py
+++ b/qiskit/chemistry/core/hamiltonian.py
@@ -26,7 +26,6 @@
 from .chemistry_operator import (ChemistryOperator,
                                  MolecularGroundStateResult,
                                  DipoleTuple)
-from ..components.initial_states import HartreeFock
 
 logger = logging.getLogger(__name__)
 
@@ -264,7 +263,7 @@ def _dipole_op(dipole_integrals, axis):
         logger.info('Molecule num spin orbitals: %s, remaining for processing: %s',
                     nspinorbs, new_nspinorbs)
 
-        self._add_molecule_info(self.INFO_NUM_PARTICLES, [new_num_alpha, new_num_beta])
+        self._add_molecule_info(self.INFO_NUM_PARTICLES, (new_num_alpha, new_num_beta))
         self._add_molecule_info(self.INFO_NUM_ORBITALS, new_nspinorbs)
         self._add_molecule_info(self.INFO_TWO_QUBIT_REDUCTION,
                                 self._two_qubit_reduction
@@ -306,11 +305,12 @@ def _process_z2symmetry_reduction(self, qubit_op, aux_ops):
                     aux_ops[i] = None  # Discard since no meaningful measurement can be done
 
             if self._z2symmetry_reduction == 'auto':
-                hf_state = HartreeFock(num_orbitals=self._molecule_info[self.INFO_NUM_ORBITALS],
-                                       qubit_mapping=self._qubit_mapping,
-                                       two_qubit_reduction=self._two_qubit_reduction,
-                                       num_particles=self._molecule_info[self.INFO_NUM_PARTICLES])
-                z2_symmetries = Hamiltonian._pick_sector(z2_symmetries, hf_state.bitstr)
+                from ..circuit.library.initial_states.hartree_fock import _build_bitstr
+                hf_bitstr = _build_bitstr(num_orbitals=self._molecule_info['num_orbitals'],
+                                          qubit_mapping=self._qubit_mapping,
+                                          two_qubit_reduction=self._two_qubit_reduction,
+                                          num_particles=self._molecule_info['num_particles'])
+                z2_symmetries = Hamiltonian._pick_sector(z2_symmetries, hf_bitstr)
             else:
                 if len(self._z2symmetry_reduction) != len(z2_symmetries.symmetries):
                     raise QiskitChemistryError('z2symmetry_reduction tapering values list has '
diff --git a/qiskit/chemistry/transformations/fermionic_transformation.py b/qiskit/chemistry/transformations/fermionic_transformation.py
index 36e39b718a..e16c04bc59 100644
--- a/qiskit/chemistry/transformations/fermionic_transformation.py
+++ b/qiskit/chemistry/transformations/fermionic_transformation.py
@@ -33,7 +33,6 @@
 from qiskit.chemistry.components.variational_forms import UCCSD
 
 from .transformation import Transformation
-from ..components.initial_states import HartreeFock
 
 logger = logging.getLogger(__name__)
 
@@ -364,7 +363,7 @@ def _dipole_op(dipole_integrals: np.ndarray, axis: str) \
         logger.info('Molecule num spin orbitals: %s, remaining for processing: %s',
                     nspinorbs, new_nspinorbs)
 
-        self._molecule_info['num_particles'] = [new_num_alpha, new_num_beta]
+        self._molecule_info['num_particles'] = (new_num_alpha, new_num_beta)
         self._molecule_info['num_orbitals'] = new_nspinorbs
         reduction = self._two_qubit_reduction if self._qubit_mapping == 'parity' else False
         self._molecule_info['two_qubit_reduction'] = reduction
@@ -425,11 +424,12 @@ def _process_z2symmetry_reduction(self,
                     aux_ops[i] = None  # Discard since no meaningful measurement can be done
 
             if self._z2symmetry_reduction == 'auto':
-                hf_state = HartreeFock(num_orbitals=self._molecule_info['num_orbitals'],
-                                       qubit_mapping=self._qubit_mapping,
-                                       two_qubit_reduction=self._two_qubit_reduction,
-                                       num_particles=self._molecule_info['num_particles'])
-                z2_symmetries = FermionicTransformation._pick_sector(z2_symmetries, hf_state.bitstr)
+                from ..circuit.library.initial_states.hartree_fock import _build_bitstr
+                hf_bitstr = _build_bitstr(num_orbitals=self._molecule_info['num_orbitals'],
+                                          qubit_mapping=self._qubit_mapping,
+                                          two_qubit_reduction=self._two_qubit_reduction,
+                                          num_particles=self._molecule_info['num_particles'])
+                z2_symmetries = FermionicTransformation._pick_sector(z2_symmetries, hf_bitstr)
             else:
                 if len(self._z2symmetry_reduction) != len(z2_symmetries.symmetries):
                     raise QiskitChemistryError('z2symmetry_reduction tapering values list has '
diff --git a/test/chemistry/circuit/library/test_hartree_fock.py b/test/chemistry/circuit/library/test_hartree_fock.py
new file mode 100644
index 0000000000..c91aa3dc86
--- /dev/null
+++ b/test/chemistry/circuit/library/test_hartree_fock.py
@@ -0,0 +1,62 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Test Hartree Fock initial state circuit."""
+
+import unittest
+from test.chemistry import QiskitChemistryTestCase
+
+from qiskit import QuantumCircuit
+from qiskit.chemistry.circuit.library import HartreeFock
+
+
+class TestHartreeFock(QiskitChemistryTestCase):
+    """ Initial State HartreeFock tests """
+
+    def test_qubits_4_jw_h2(self):
+        """ qubits 4 jw h2 test """
+        state = HartreeFock(4, (1, 1), 'jordan_wigner', False)
+        ref = QuantumCircuit(4)
+        ref.x([0, 2])
+        self.assertEqual(state, ref)
+
+    def test_qubits_4_py_h2(self):
+        """ qubits 4 py h2 test """
+        state = HartreeFock(4, (1, 1), 'parity', False)
+        ref = QuantumCircuit(4)
+        ref.x([0, 1])
+        self.assertEqual(state, ref)
+
+    def test_qubits_4_bk_h2(self):
+        """ qubits 4 bk h2 test """
+        state = HartreeFock(4, (1, 1), 'bravyi_kitaev', False)
+        ref = QuantumCircuit(4)
+        ref.x([0, 1, 2])
+        self.assertEqual(state, ref)
+
+    def test_qubits_2_py_h2(self):
+        """ qubits 2 py h2 test """
+        state = HartreeFock(4, 2, 'parity', True)
+        ref = QuantumCircuit(2)
+        ref.x(0)
+        self.assertEqual(state, ref)
+
+    def test_qubits_6_py_lih(self):
+        """ qubits 6 py lih test """
+        state = HartreeFock(10, (1, 1), 'parity', True, [1, 2])
+        ref = QuantumCircuit(6)
+        ref.x([0, 1])
+        self.assertEqual(state, ref)
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/test/chemistry/circuit/library/test_vscf.py b/test/chemistry/circuit/library/test_vscf.py
new file mode 100644
index 0000000000..dbc4e38a30
--- /dev/null
+++ b/test/chemistry/circuit/library/test_vscf.py
@@ -0,0 +1,44 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2018, 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Test the VSCF initial state."""
+
+import unittest
+from test.chemistry import QiskitChemistryTestCase
+from qiskit import QuantumCircuit
+from qiskit.chemistry.circuit.library import VSCF
+
+
+class TestVSCF(QiskitChemistryTestCase):
+    """ Initial State vscf tests """
+
+    def test_qubits_4(self):
+        """Test 2 modes 2 modals."""
+        basis = [2, 2]
+        vscf = VSCF(basis)
+        ref = QuantumCircuit(4)
+        ref.x([0, 2])
+
+        self.assertEqual(ref, vscf)
+
+    def test_qubits_5(self):
+        """Test 2 modes 2 modals for the first mode and 3 modals for the second."""
+        basis = [2, 3]
+        vscf = VSCF(basis)
+        ref = QuantumCircuit(5)
+        ref.x([0, 2])
+
+        self.assertEqual(ref, vscf)
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/test/chemistry/test_adapt_vqe.py b/test/chemistry/test_adapt_vqe.py
index eee14a0a64..abd9f47ee5 100644
--- a/test/chemistry/test_adapt_vqe.py
+++ b/test/chemistry/test_adapt_vqe.py
@@ -20,7 +20,7 @@
 from qiskit.aqua.algorithms import VQE
 from qiskit.chemistry import QiskitChemistryError
 from qiskit.chemistry.components.variational_forms import UCCSD
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.aqua.components.optimizers import L_BFGS_B
 from qiskit.chemistry.algorithms.ground_state_solvers import AdaptVQE, VQEUCCSDFactory
 from qiskit.chemistry.transformations import FermionicTransformation
diff --git a/test/chemistry/test_app_mgse.py b/test/chemistry/test_app_mgse.py
index ed6823210f..1e1b08ea9c 100644
--- a/test/chemistry/test_app_mgse.py
+++ b/test/chemistry/test_app_mgse.py
@@ -25,7 +25,7 @@
 from qiskit.aqua.components.optimizers import SLSQP
 from qiskit.chemistry import QiskitChemistryError
 from qiskit.chemistry.applications import MolecularGroundStateEnergy
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.chemistry.components.variational_forms import UCCSD
 from qiskit.chemistry.core import QubitMappingType
 from qiskit.chemistry.drivers import PySCFDriver, UnitsType
diff --git a/test/chemistry/test_bopes_sampler.py b/test/chemistry/test_bopes_sampler.py
index 97a7ec183e..1ee2538a33 100644
--- a/test/chemistry/test_bopes_sampler.py
+++ b/test/chemistry/test_bopes_sampler.py
@@ -23,7 +23,7 @@
 from qiskit.aqua.components.optimizers import AQGD
 from qiskit.aqua.operators import PauliExpectation
 from qiskit.chemistry.algorithms.pes_samplers.bopes_sampler import BOPESSampler
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.chemistry.drivers import Molecule, PySCFDriver
 from qiskit.chemistry.algorithms.ground_state_solvers import GroundStateEigensolver
 from qiskit.chemistry.algorithms.pes_samplers.potentials.morse_potential import MorsePotential
@@ -65,7 +65,8 @@ def test_h2_bopes_sampler(self):
                               sq_list=f_t._molecule_info['z2_symmetries'].sq_list
                               )
         var_form = RealAmplitudes(qubitop.num_qubits, reps=1, entanglement='full',
-                                  initial_state=i_state, skip_unentangled_qubits=False)
+                                  skip_unentangled_qubits=False)
+        var_form.compose(i_state, front=True)
 
         # Classical optimizer:
         # Analytic Quantum Gradient Descent (AQGD) (with Epochs)
diff --git a/test/chemistry/test_chc_vscf.py b/test/chemistry/test_chc_vscf.py
index 7bdfa9f421..bf26ef4219 100644
--- a/test/chemistry/test_chc_vscf.py
+++ b/test/chemistry/test_chc_vscf.py
@@ -13,6 +13,7 @@
 """ Test of CHC and VSCF Aqua extensions """
 
 import unittest
+import warnings
 
 from test.chemistry import QiskitChemistryTestCase
 
@@ -62,7 +63,9 @@ def test_chc_vscf(self):
         bosonic_op = BosonicOperator(co2_2modes_2modals_2body, basis)
         qubit_op = bosonic_op.mapping('direct', threshold=1e-5)
 
-        init_state = VSCF(basis)
+        with warnings.catch_warnings():
+            warnings.filterwarnings('ignore', category=DeprecationWarning)
+            init_state = VSCF(basis)
 
         num_qubits = sum(basis)
         uvcc_varform = UVCC(num_qubits, basis, [0, 1])
diff --git a/test/chemistry/test_core_hamiltonian.py b/test/chemistry/test_core_hamiltonian.py
index 227ffa3f9c..23b3597a76 100644
--- a/test/chemistry/test_core_hamiltonian.py
+++ b/test/chemistry/test_core_hamiltonian.py
@@ -44,7 +44,7 @@ def _validate_vars(self, core, energy_shift=0.0, ph_energy_shift=0.0):
 
     def _validate_info(self, core, num_particles=None,
                        num_orbitals=4, actual_two_qubit_reduction=False):
-        num_particles = num_particles if num_particles is not None else [1, 1]
+        num_particles = num_particles if num_particles is not None else (1, 1)
         z2symmetries = core.molecule_info.pop('z2symmetries')
         self.assertEqual(z2symmetries.is_empty(), True)
         self.assertEqual(core.molecule_info, {'num_particles': num_particles,
diff --git a/test/chemistry/test_core_hamiltonian_orb_reduce.py b/test/chemistry/test_core_hamiltonian_orb_reduce.py
index 8573c43d61..8bd066b97c 100644
--- a/test/chemistry/test_core_hamiltonian_orb_reduce.py
+++ b/test/chemistry/test_core_hamiltonian_orb_reduce.py
@@ -44,7 +44,7 @@ def _validate_vars(self, core, energy_shift=0.0, ph_energy_shift=0.0):
 
     def _validate_info(self, core, num_particles=None,
                        num_orbitals=12, actual_two_qubit_reduction=False):
-        num_particles = num_particles if num_particles is not None else [2, 2]
+        num_particles = num_particles if num_particles is not None else (2, 2)
         z2symmetries = core.molecule_info.pop('z2symmetries')
         self.assertEqual(z2symmetries.is_empty(), True)
         self.assertEqual(core.molecule_info, {'num_particles': num_particles,
@@ -96,7 +96,7 @@ def test_freeze_core(self):
         warnings.filterwarnings('always', category=DeprecationWarning)
         qubit_op, _ = core.run(self.qmolecule)
         self._validate_vars(core, energy_shift=-7.7962196)
-        self._validate_info(core, num_particles=[1, 1], num_orbitals=10)
+        self._validate_info(core, num_particles=(1, 1), num_orbitals=10)
         self._validate_input_object(qubit_op, num_qubits=10, num_paulis=276)
 
     def test_freeze_core_orb_reduction(self):
@@ -110,7 +110,7 @@ def test_freeze_core_orb_reduction(self):
         warnings.filterwarnings('always', category=DeprecationWarning)
         qubit_op, _ = core.run(self.qmolecule)
         self._validate_vars(core, energy_shift=-7.7962196)
-        self._validate_info(core, num_particles=[1, 1], num_orbitals=6)
+        self._validate_info(core, num_particles=(1, 1), num_orbitals=6)
         self._validate_input_object(qubit_op, num_qubits=6, num_paulis=118)
 
     def test_freeze_core_all_reduction(self):
@@ -124,7 +124,7 @@ def test_freeze_core_all_reduction(self):
         warnings.filterwarnings('always', category=DeprecationWarning)
         qubit_op, _ = core.run(self.qmolecule)
         self._validate_vars(core, energy_shift=-7.7962196)
-        self._validate_info(core, num_particles=[1, 1], num_orbitals=6,
+        self._validate_info(core, num_particles=(1, 1), num_orbitals=6,
                             actual_two_qubit_reduction=True)
         self._validate_input_object(qubit_op, num_qubits=4, num_paulis=100)
 
@@ -139,7 +139,7 @@ def test_freeze_core_all_reduction_ph(self):
         warnings.filterwarnings('always', category=DeprecationWarning)
         qubit_op, _ = core.run(self.qmolecule)
         self._validate_vars(core, energy_shift=-7.7962196, ph_energy_shift=-1.05785247)
-        self._validate_info(core, num_particles=[1, 1], num_orbitals=6,
+        self._validate_info(core, num_particles=(1, 1), num_orbitals=6,
                             actual_two_qubit_reduction=True)
         self._validate_input_object(qubit_op, num_qubits=4, num_paulis=52)
 
diff --git a/test/chemistry/test_end2end_with_iqpe.py b/test/chemistry/test_end2end_with_iqpe.py
index 459224563e..9441e4fc18 100644
--- a/test/chemistry/test_end2end_with_iqpe.py
+++ b/test/chemistry/test_end2end_with_iqpe.py
@@ -23,7 +23,7 @@
 from qiskit.aqua.operators import Z2Symmetries
 from qiskit.chemistry.drivers import PySCFDriver, UnitsType
 from qiskit.chemistry import FermionicOperator, QiskitChemistryError
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 
 
 @ddt
diff --git a/test/chemistry/test_end2end_with_qpe.py b/test/chemistry/test_end2end_with_qpe.py
index f990dfdc50..0261d54691 100644
--- a/test/chemistry/test_end2end_with_qpe.py
+++ b/test/chemistry/test_end2end_with_qpe.py
@@ -24,7 +24,7 @@
 from qiskit.aqua.operators import Z2Symmetries
 from qiskit.chemistry.drivers import PySCFDriver, UnitsType
 from qiskit.chemistry import FermionicOperator, QiskitChemistryError
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 
 
 @ddt
diff --git a/test/chemistry/test_fermionic_transformation.py b/test/chemistry/test_fermionic_transformation.py
index 0c5345f826..82ad8663ba 100644
--- a/test/chemistry/test_fermionic_transformation.py
+++ b/test/chemistry/test_fermionic_transformation.py
@@ -44,7 +44,7 @@ def _validate_vars(self, fermionic_transformation, energy_shift=0.0, ph_energy_s
 
     def _validate_info(self, fermionic_transformation, num_particles=None,
                        num_orbitals=4, actual_two_qubit_reduction=False):
-        num_particles = num_particles if num_particles is not None else [1, 1]
+        num_particles = num_particles if num_particles is not None else (1, 1)
         z2symmetries = fermionic_transformation.molecule_info.pop('z2_symmetries')
         self.assertEqual(z2symmetries.is_empty(), True)
         self.assertEqual(fermionic_transformation.molecule_info,
diff --git a/test/chemistry/test_fermionic_transformation_orb_reduce.py b/test/chemistry/test_fermionic_transformation_orb_reduce.py
index 8a95edea1f..4d7f7ea635 100644
--- a/test/chemistry/test_fermionic_transformation_orb_reduce.py
+++ b/test/chemistry/test_fermionic_transformation_orb_reduce.py
@@ -43,7 +43,7 @@ def _validate_vars(self, fermionic_transformation, energy_shift=0.0, ph_energy_s
 
     def _validate_info(self, fermionic_transformation, num_particles=None,
                        num_orbitals=12, actual_two_qubit_reduction=False):
-        num_particles = num_particles if num_particles is not None else [2, 2]
+        num_particles = num_particles if num_particles is not None else (2, 2)
         z2symmetries = fermionic_transformation.molecule_info.pop('z2_symmetries')
         self.assertEqual(z2symmetries.is_empty(), True)
         self.assertEqual(fermionic_transformation.molecule_info,
@@ -96,7 +96,7 @@ def test_freeze_core(self):
 
         qubit_op, _ = fermionic_transformation.transform(self.driver)
         self._validate_vars(fermionic_transformation, energy_shift=-7.7962196)
-        self._validate_info(fermionic_transformation, num_particles=[1, 1], num_orbitals=10)
+        self._validate_info(fermionic_transformation, num_particles=(1, 1), num_orbitals=10)
         self._validate_input_object(qubit_op, num_qubits=10, num_paulis=276)
 
     def test_freeze_core_orb_reduction(self):
@@ -110,7 +110,7 @@ def test_freeze_core_orb_reduction(self):
 
         qubit_op, _ = fermionic_transformation.transform(self.driver)
         self._validate_vars(fermionic_transformation, energy_shift=-7.7962196)
-        self._validate_info(fermionic_transformation, num_particles=[1, 1], num_orbitals=6)
+        self._validate_info(fermionic_transformation, num_particles=(1, 1), num_orbitals=6)
         self._validate_input_object(qubit_op, num_qubits=6, num_paulis=118)
 
     def test_freeze_core_all_reduction(self):
@@ -124,7 +124,7 @@ def test_freeze_core_all_reduction(self):
 
         qubit_op, _ = fermionic_transformation.transform(self.driver)
         self._validate_vars(fermionic_transformation, energy_shift=-7.7962196)
-        self._validate_info(fermionic_transformation, num_particles=[1, 1], num_orbitals=6,
+        self._validate_info(fermionic_transformation, num_particles=(1, 1), num_orbitals=6,
                             actual_two_qubit_reduction=True)
         self._validate_input_object(qubit_op, num_qubits=4, num_paulis=100)
 
@@ -140,7 +140,7 @@ def test_freeze_core_all_reduction_ph(self):
         qubit_op, _ = fermionic_transformation.transform(self.driver)
         self._validate_vars(fermionic_transformation, energy_shift=-7.7962196,
                             ph_energy_shift=-1.05785247)
-        self._validate_info(fermionic_transformation, num_particles=[1, 1], num_orbitals=6,
+        self._validate_info(fermionic_transformation, num_particles=(1, 1), num_orbitals=6,
                             actual_two_qubit_reduction=True)
         self._validate_input_object(qubit_op, num_qubits=4, num_paulis=52)
 
diff --git a/test/chemistry/test_initial_state_hartree_fock.py b/test/chemistry/test_initial_state_hartree_fock.py
index 4186d3854b..df8e9dccaa 100644
--- a/test/chemistry/test_initial_state_hartree_fock.py
+++ b/test/chemistry/test_initial_state_hartree_fock.py
@@ -18,7 +18,6 @@
 
 import numpy as np
 from ddt import ddt, idata, unpack
-from qiskit import QuantumCircuit
 from qiskit.chemistry.components.initial_states import HartreeFock
 from qiskit.aqua.operators import StateFn
 from qiskit.chemistry import QiskitChemistryError
@@ -126,45 +125,5 @@ def test_hf_value(self, mapping):
         self.assertAlmostEqual(fermionic_transformation._hf_energy, hf_energy, places=6)
 
 
-@ddt
-class TestHartreeFock(QiskitChemistryTestCase):
-    """ Initial State HartreeFock tests """
-
-    def test_qubits_4_jw_h2(self):
-        """ qubits 4 jw h2 test """
-        state = HartreeFock(4, (1, 1), 'jordan_wigner', False)
-        ref = QuantumCircuit(4)
-        ref.x([0, 2])
-        self.assertEqual(state, ref)
-
-    def test_qubits_4_py_h2(self):
-        """ qubits 4 py h2 test """
-        state = HartreeFock(4, (1, 1), 'parity', False)
-        ref = QuantumCircuit(4)
-        ref.x([0, 1])
-        self.assertEqual(state, ref)
-
-    def test_qubits_4_bk_h2(self):
-        """ qubits 4 bk h2 test """
-        state = HartreeFock(4, (1, 1), 'bravyi_kitaev', False)
-        ref = QuantumCircuit(4)
-        ref.x([0, 1, 2])
-        self.assertEqual(state, ref)
-
-    def test_qubits_2_py_h2(self):
-        """ qubits 2 py h2 test """
-        state = HartreeFock(4, 2, 'parity', True)
-        ref = QuantumCircuit(2)
-        ref.x(0)
-        self.assertEqual(state, ref)
-
-    def test_qubits_6_py_lih(self):
-        """ qubits 6 py lih test """
-        state = HartreeFock(10, (1, 1), 'parity', True, [1, 2])
-        ref = QuantumCircuit(6)
-        ref.x([0, 1])
-        self.assertEqual(state, ref)
-
-
 if __name__ == '__main__':
     unittest.main()
diff --git a/test/chemistry/test_initial_state_vscf.py b/test/chemistry/test_initial_state_vscf.py
index 0d579135d0..8e51ddaa58 100644
--- a/test/chemistry/test_initial_state_vscf.py
+++ b/test/chemistry/test_initial_state_vscf.py
@@ -10,13 +10,12 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-""" Test Initial State HartreeFock """
+""" Test Initial State VSCF """
 
 import unittest
 import warnings
 from test.chemistry import QiskitChemistryTestCase
 import numpy as np
-from qiskit import QuantumCircuit
 from qiskit.chemistry.components.initial_states import VSCF
 
 
@@ -50,27 +49,5 @@ def test_qubits_5(self):
                                             0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])
 
 
-class TestVSCF(QiskitChemistryTestCase):
-    """ Initial State vscf tests """
-
-    def test_qubits_4(self):
-        """ 2 modes 2 modals - test """
-        basis = [2, 2]
-        vscf = VSCF(basis)
-        ref = QuantumCircuit(4)
-        ref.x([0, 2])
-
-        self.assertEqual(ref, vscf)
-
-    def test_qubits_5(self):
-        """ 2 modes 2 modals for the first mode and 3 modals for the second - test """
-        basis = [2, 3]
-        vscf = VSCF(basis)
-        ref = QuantumCircuit(5)
-        ref.x([0, 2])
-
-        self.assertEqual(ref, vscf)
-
-
 if __name__ == '__main__':
     unittest.main()
diff --git a/test/chemistry/test_qeom_vqe.py b/test/chemistry/test_qeom_vqe.py
index d17cfc147a..ae0777fdf8 100644
--- a/test/chemistry/test_qeom_vqe.py
+++ b/test/chemistry/test_qeom_vqe.py
@@ -29,7 +29,7 @@
 from qiskit.chemistry.drivers import PySCFDriver, UnitsType
 from qiskit.chemistry.core import Hamiltonian, TransformationType, QubitMappingType
 from qiskit.chemistry.components.variational_forms import UCCSD
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 
 
 class TestEomVQE(QiskitAquaTestCase):
diff --git a/test/chemistry/test_readme_sample.py b/test/chemistry/test_readme_sample.py
index 485aec03e0..6840b0fc49 100644
--- a/test/chemistry/test_readme_sample.py
+++ b/test/chemistry/test_readme_sample.py
@@ -79,12 +79,15 @@ def print(*args):
         optimizer = L_BFGS_B()
 
         # setup the initial state for the variational form
-        from qiskit.chemistry.components.initial_states import HartreeFock
+        from qiskit.chemistry.circuit.library import HartreeFock
         init_state = HartreeFock(num_spin_orbitals, num_particles)
 
         # setup the variational form for VQE
         from qiskit.circuit.library import TwoLocal
-        var_form = TwoLocal(num_qubits, ['ry', 'rz'], 'cz', initial_state=init_state)
+        var_form = TwoLocal(num_qubits, ['ry', 'rz'], 'cz')
+
+        # add the initial state
+        var_form.compose(init_state, front=True)
 
         # setup and run VQE
         from qiskit.aqua.algorithms import VQE
diff --git a/test/chemistry/test_swaprz.py b/test/chemistry/test_swaprz.py
index 76febe3a42..199d35fe52 100644
--- a/test/chemistry/test_swaprz.py
+++ b/test/chemistry/test_swaprz.py
@@ -19,7 +19,7 @@
 from qiskit.aqua import QuantumInstance, aqua_globals
 from qiskit.aqua.algorithms import VQE
 from qiskit.aqua.components.optimizers import SLSQP
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.chemistry.core import QubitMappingType
 from qiskit.chemistry.drivers import HDF5Driver
 from qiskit.chemistry.algorithms.ground_state_solvers import GroundStateEigensolver
@@ -57,7 +57,8 @@ def test_excitation_preserving(self):
             qubit_mapping=fermionic_transformation._qubit_mapping,
             two_qubit_reduction=fermionic_transformation._two_qubit_reduction)
 
-        wavefunction = ExcitationPreserving(qubit_op.num_qubits, initial_state=initial_state)
+        wavefunction = ExcitationPreserving(qubit_op.num_qubits)
+        wavefunction.compose(initial_state, front=True, inplace=True)
 
         solver = VQE(var_form=wavefunction, optimizer=optimizer,
                      quantum_instance=QuantumInstance(BasicAer.get_backend('statevector_simulator'),
diff --git a/test/chemistry/test_symmetries.py b/test/chemistry/test_symmetries.py
index 930907aaf0..a4c2513349 100644
--- a/test/chemistry/test_symmetries.py
+++ b/test/chemistry/test_symmetries.py
@@ -22,7 +22,7 @@
 from qiskit.chemistry import QiskitChemistryError
 from qiskit.chemistry.drivers import PySCFDriver, UnitsType
 from qiskit.chemistry.components.variational_forms import UCCSD
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.chemistry.algorithms.ground_state_solvers import GroundStateEigensolver
 from qiskit.chemistry.core import TransformationType, QubitMappingType
 from qiskit.chemistry.transformations import FermionicTransformation
diff --git a/test/chemistry/test_uccsd_advanced.py b/test/chemistry/test_uccsd_advanced.py
index e85699c9c9..ad03a0e29a 100644
--- a/test/chemistry/test_uccsd_advanced.py
+++ b/test/chemistry/test_uccsd_advanced.py
@@ -20,7 +20,7 @@
 from qiskit.aqua.algorithms import VQE
 from qiskit.aqua.components.optimizers import SLSQP
 from qiskit.chemistry import QiskitChemistryError
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.chemistry.components.variational_forms import UCCSD
 from qiskit.chemistry.drivers import PySCFDriver, UnitsType
 from qiskit.chemistry.algorithms.ground_state_solvers import GroundStateEigensolver
diff --git a/test/chemistry/test_uccsd_hartree_fock.py b/test/chemistry/test_uccsd_hartree_fock.py
index 426658b55c..90fc260955 100644
--- a/test/chemistry/test_uccsd_hartree_fock.py
+++ b/test/chemistry/test_uccsd_hartree_fock.py
@@ -19,7 +19,8 @@
 from qiskit.aqua.algorithms import VQE
 from qiskit.aqua.components.optimizers import SLSQP, SPSA
 from qiskit.aqua.operators import AerPauliExpectation, PauliExpectation
-from qiskit.chemistry.components.initial_states import HartreeFock
+
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.chemistry.components.variational_forms import UCCSD
 from qiskit.chemistry.core import QubitMappingType
 from qiskit.chemistry.drivers import HDF5Driver
@@ -48,7 +49,7 @@ def setUp(self):
         self.optimizer = SLSQP(maxiter=100)
         initial_state = HartreeFock(
             fermionic_transformation.molecule_info['num_orbitals'],
-            tuple(fermionic_transformation.molecule_info['num_particles']),
+            fermionic_transformation.molecule_info['num_particles'],
             qubit_mapping=fermionic_transformation._qubit_mapping,
             two_qubit_reduction=fermionic_transformation._two_qubit_reduction)
         self.var_form = UCCSD(
diff --git a/test/chemistry/test_uvcc_vscf.py b/test/chemistry/test_uvcc_vscf.py
index 8f75f31e3d..b723a428ef 100644
--- a/test/chemistry/test_uvcc_vscf.py
+++ b/test/chemistry/test_uvcc_vscf.py
@@ -12,6 +12,7 @@
 
 """ Test of UVCC and VSCF Aqua extensions """
 
+import warnings
 from test.chemistry import QiskitChemistryTestCase
 
 from qiskit import BasicAer
@@ -61,7 +62,9 @@ def test_uvcc_vscf(self):
         bosonic_op = BosonicOperator(co2_2modes_2modals_2body, basis)
         qubit_op = bosonic_op.mapping('direct', threshold=1e-5)
 
-        init_state = VSCF(basis)
+        with warnings.catch_warnings():
+            warnings.filterwarnings('ignore', category=DeprecationWarning)
+            init_state = VSCF(basis)
 
         num_qubits = sum(basis)
         uvcc_varform = UVCC(num_qubits, basis, [0, 1], initial_state=init_state)
diff --git a/test/chemistry/test_vqe_uccsd_adapt.py b/test/chemistry/test_vqe_uccsd_adapt.py
index af2eee5387..2fa846ab9f 100644
--- a/test/chemistry/test_vqe_uccsd_adapt.py
+++ b/test/chemistry/test_vqe_uccsd_adapt.py
@@ -22,7 +22,7 @@
 from qiskit.aqua.operators.legacy.weighted_pauli_operator import Z2Symmetries
 from qiskit.chemistry import FermionicOperator
 from qiskit.chemistry.algorithms import VQEAdapt
-from qiskit.chemistry.components.initial_states import HartreeFock
+from qiskit.chemistry.circuit.library import HartreeFock
 from qiskit.chemistry.components.variational_forms import UCCSD
 from qiskit.chemistry.drivers import PySCFDriver, UnitsType
 from qiskit.chemistry import QiskitChemistryError