# HamiltonianGate#

class qiskit.extensions.HamiltonianGate(data, time, label=None)[source]#

Bases: Gate

Class for representing evolution by a Hamiltonian operator as a gate.

This gate resolves to a UnitaryGate as $$U(t) = exp(-i t H)$$, which can be decomposed into basis gates if it is 2 qubits or less, or simulated directly in Aer for more qubits. Note that you can also directly use QuantumCircuit.hamiltonian().

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

Parameters:
• data (matrix or Operator) â€“ a hermitian operator.

• time (float or ParameterExpression) â€“ time evolution parameter.

• label (str) â€“ unitary name for backend [Default: None].

Raises:

ExtensionError â€“ if input data is not an N-qubit unitary operator.

Attributes

condition_bits#

Get Clbits in condition.

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

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.

Methods

Add a decomposition of the instruction to the SessionEquivalenceLibrary.

Return the adjoint of the unitary.

assemble()#

Assemble a QasmQobjInstruction

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]], []


• 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) â€“ List of quantum bit arguments.

• cargs (list) â€“ List of classical bit arguments.

Returns:

A tuple with single arguments.

Raises:

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

Return type:
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()[source]#

Return the conjugate of the Hamiltonian.

control(num_ctrl_qubits=1, label=None, ctrl_state=None)#

Return controlled version of gate. See ControlledGate for usage.

Parameters:
• num_ctrl_qubits (int) â€“ number of controls to add to gate (default=1)

• label (str | None) â€“ optional gate label

• ctrl_state (int | str | None) â€“ The control state in decimal or as a bitstring (e.g. â€˜111â€™). 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 â€“ unrecognized mode or invalid ctrl_state

copy(name=None)#

Copy of the instruction.

Parameters:

name (str) â€“ 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()[source]#

Return the adjoint of the unitary.

is_parameterized()#

Return True .IFF. instruction is parameterized else False

power(exponent)#

Creates a unitary gate as gate^exponent.

Parameters:

exponent (float) â€“ Gate^exponent

Returns:

To which to_matrix is self.to_matrix^exponent.

Return type:

qiskit.extensions.UnitaryGate

Raises:

CircuitError â€“ If Gate is not unitary

qasm()[source]#

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

Deprecated since version 0.25.0: The method qiskit.extensions.hamiltonian_gate.HamiltonianGate.qasm() is deprecated as of qiskit-terra 0.25.0. It will be removed no earlier than 3 months after the release date.

repeat(n)#

Creates an instruction with gate repeated n amount of times.

Parameters:

n (int) â€“ Number of times to repeat the instruction

Returns:

Containing the definition.

Return type:

qiskit.circuit.Instruction

Raises:

CircuitError â€“ If n < 1.

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(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) â€“ other instruction.

Returns:

are self and other equal up to parameter expressions.

Return type:

bool

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

transpose()[source]#

Return the transpose of the Hamiltonian.

validate_parameter(parameter)[source]#

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