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HamiltonianGate

class HamiltonianGate(data, time, label=None)

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Bases: qiskit.circuit.gate.Gate

Class for representing evolution by a Hermitian Hamiltonian operator as a gate. This gate resolves to a UnitaryGate U(t) = exp(-1j * t * H), which can be decomposed into basis gates if it is 2 qubits or less, or simulated directly in Aer for more qubits.

Create a gate from a hamiltonian operator and evolution time parameter t

Parameters

  • data (matrix or Operator) – a hermitian operator.
  • time (float) – time evolution parameter.
  • label (str) – unitary name for backend [Default: None].

Raises

ExtensionError – if input data is not an N-qubit unitary operator.


Methods

add_decomposition

HamiltonianGate.add_decomposition(decomposition)

Add a decomposition of the instruction to the SessionEquivalenceLibrary.

adjoint

HamiltonianGate.adjoint()

Return the adjoint of the unitary.

assemble

HamiltonianGate.assemble()

Assemble a QasmQobjInstruction

broadcast_arguments

HamiltonianGate.broadcast_arguments(qargs, cargs)

Validation and handling of the arguments and its relationship.

For example, cx([q[0],q[1]], q[2]) means cx(q[0], q[2]); cx(q[1], q[2]). This method yields the arguments in the right grouping. In the given example:

in: [[q[0],q[1]], q[2]],[]
outs: [q[0], q[2]], []
      [q[1], q[2]], []

The general broadcasting rules are:

  • If len(qargs) == 1:

    [q[0], q[1]] -> [q[0]],[q[1]]
  • If len(qargs) == 2:

    [[q[0], q[1]], [r[0], r[1]]] -> [q[0], r[0]], [q[1], r[1]]
    [[q[0]], [r[0], r[1]]]       -> [q[0], r[0]], [q[0], r[1]]
    [[q[0], q[1]], [r[0]]]       -> [q[0], r[0]], [q[1], r[0]]
  • If len(qargs) >= 3:

    [q[0], q[1]], [r[0], r[1]],  ...] -> [q[0], r[0], ...], [q[1], r[1], ...]

Parameters

  • qargs (List) – List of quantum bit arguments.
  • cargs (List) – List of classical bit arguments.

Return type

Tuple[List, List]

Returns

A tuple with single arguments.

Raises

CircuitError – If the input is not valid. For example, the number of arguments does not match the gate expectation.

c_if

HamiltonianGate.c_if(classical, val)

Set a classical equality condition on this instruction between the register or cbit classical and value val.

Note

This is a setter method, not an additive one. Calling this multiple times will silently override any previously set condition; it does not stack.

conjugate

HamiltonianGate.conjugate()

Return the conjugate of the Hamiltonian.

control

HamiltonianGate.control(num_ctrl_qubits=1, label=None, ctrl_state=None)

Return controlled version of gate. See ControlledGate for usage.

Parameters

  • num_ctrl_qubits (int) – number of controls to add to gate (default=1)
  • label (Optional[str]) – optional gate label
  • ctrl_state (Union[str, int, None]) – The control state in decimal or as a bitstring (e.g. ‘111’). If None, use 2**num_ctrl_qubits-1.

Returns

Controlled version of gate. This default algorithm uses num_ctrl_qubits-1 ancillae qubits so returns a gate of size num_qubits + 2*num_ctrl_qubits - 1.

Return type

qiskit.circuit.ControlledGate

Raises

QiskitError – unrecognized mode or invalid ctrl_state

copy

HamiltonianGate.copy(name=None)

Copy of the instruction.

Parameters

name (str) – name to be given to the copied circuit, if None then the name stays the same.

Returns

a copy of the current instruction, with the name

updated if it was provided

Return type

qiskit.circuit.Instruction

inverse

HamiltonianGate.inverse()

Return the adjoint of the unitary.

is_parameterized

HamiltonianGate.is_parameterized()

Return True .IFF. instruction is parameterized else False

power

HamiltonianGate.power(exponent)

Creates a unitary gate as gate^exponent.

Parameters

exponent (float) – Gate^exponent

Returns

To which to_matrix is self.to_matrix^exponent.

Return type

qiskit.extensions.UnitaryGate

Raises

CircuitError – If Gate is not unitary

qasm

HamiltonianGate.qasm()

Raise an error, as QASM is not defined for the HamiltonianGate.

repeat

HamiltonianGate.repeat(n)

Creates an instruction with gate repeated n amount of times.

Parameters

n (int) – Number of times to repeat the instruction

Returns

Containing the definition.

Return type

qiskit.circuit.Instruction

Raises

CircuitError – If n < 1.

reverse_ops

HamiltonianGate.reverse_ops()

For a composite instruction, reverse the order of sub-instructions.

This is done by recursively reversing all sub-instructions. It does not invert any gate.

Returns

a new instruction with

sub-instructions reversed.

Return type

qiskit.circuit.Instruction

soft_compare

HamiltonianGate.soft_compare(other)

Soft comparison between gates. Their names, number of qubits, and classical bit numbers must match. The number of parameters must match. Each parameter is compared. If one is a ParameterExpression then it is not taken into account.

Parameters

other (instruction) – other instruction.

Returns

are self and other equal up to parameter expressions.

Return type

bool

to_matrix

HamiltonianGate.to_matrix()

Return a Numpy.array for the gate unitary matrix.

Returns

if the Gate subclass has a matrix definition.

Return type

np.ndarray

Raises

CircuitError – If a Gate subclass does not implement this method an exception will be raised when this base class method is called.

transpose

HamiltonianGate.transpose()

Return the transpose of the Hamiltonian.

validate_parameter

HamiltonianGate.validate_parameter(parameter)

Hamiltonian parameter has to be an ndarray, operator or float.


Attributes

condition_bits

Get Clbits in condition.

Return type

List[Clbit]

decompositions

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition

Return definition in terms of other basic gates.

duration

Get the duration.

label

Return instruction label

Return type

str

name

Return the name.

num_clbits

Return the number of clbits.

num_qubits

Return the number of qubits.

params

return instruction params.

unit

Get the time unit of duration.

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