quairkit.core.state.backend.base¶

class quairkit.core.state.backend.base.State(sys_dim, dtype=None, device=None)¶

The abstract base class for all quantum state backends in QuAIRKit.

Parameters:¶

sys_dim : List[int]¶

a list of dimensions for each system.

property dtype : dtype¶

The data type of this state

property device : device¶

The device of this state

property system_dim : list[int]¶

The list of dimensions for each system

property dim : int¶

The dimension of this state

are_qubits()¶

Whether all systems are qubits

are_qutrits()¶

Whether all systems are qutrits

property num_systems : int¶

The number of systems

property num_qubits : int¶

The number of qubits of this state, when all systems are qubits

abstract clone()¶

Return a copy of the quantum state.

abstract measure(system_idx, shots, measure_op)¶

Measure the quantum state with the given measurement operator.

Parameters:¶

system_idx : int | List[int] | None¶

the system indices to be measured.

shots : int | None¶

the number of measurement shots.

measure_op : str | Tensor | None¶

the measurement operator.

Returns:¶

A tensor containing the measurement results.

Return type:¶

Tensor

abstract expec_val(hamiltonian, shots, decompose)¶

The expectation value of the observable with respect to the quantum state.

Parameters:¶

hamiltonian : Hamiltonian¶

Input observable.

shots : int | None¶

the total number of shots to measure.

decompose : bool¶

If decompose is True, it will return the expectation value of each term.

Returns:¶

The measured expectation value (per term) of the input observable for the quantum state.

Return type:¶

Tensor