Study notes for IBM's Quantum Computation using Qikit v0.2x Exam
- Perform Operations on Quantum Circuits --- 47%
- Construct multi-qubit quantum registers
- Measure quantum circuits in classical registers
- Use single-qubit gates
- Use multi-qubit gates
- Use barrier operations
- Return the circuit depth
- Extend quantum circuits
- Return the OpenQASM string for a circuit
- Executing Experiments --- 3%
- Execute a quantum circuit
- Implement BasicAer: Python-based Simulators --- 3%
- Use the available simulators
- Implement Qasm --- 1%
- Read a QASM file and string
- Compare and Contrast Quantum Information --- 10%
- Use classical and quantum registers
- Use operators
- Measure fidelity
- Return the Experiment Results --- 7%
- Return and understand the histogram data of an experiment
- Return and understand the statevector of an experiment
- Return and understand the unitary of an experiment
- Use Qiskit Tools --- 1%
- Monitor the status of a job instance
- Display and Use System Information --- 3%
- Perform operations around the Qiskit version
- Use information gained from %quiskit_backend_overview
- Construct Visualizations --- 19%
- Draw a circuit
- Plot a histogram of data
- Plot a Bloch multivector
- Plot a Bloch vector
- Plot a QSphere
- Plot a density matrix
- Plot a gate map with error rates
- Access Aer Provider --- 6%
- Access a statevector_simulator backend
- Access a qasm_simulator backend
- Access a unitary_simulator backend
Mostly defined in /circuit/quantumcircuit.py
Can be done explicitly (qr = QuantumRegister(numqubits, 'name')) or implicitly (qc = QuantumCircuit(numqubits, numclbits)).
QuantumRegister is based on Register, although the classical vs quantum differentiation is hidden in the type of Bit used.
circuit.measure(qubit, clbit)
circuit.measure_active(inplace: bool = True) adds measuremeant to all ACTIVE qubits.
circuit.measure_all(inplace: bool = True, add_bits: bool = True) adds measuremeant to ALL qubits. Will add classical bits as necessary.
NOTE - There is a circuit.remove_final_measurement() that removes all the measures and cleans up any now unused classical bits.
All are defined (sort of... methods are defined that import the required gate from /library/standard_gates/ and appends it to the circuit) way down near the bottom of /circuit/quantumcircuit.py
circuit.h(qubit)circuit.i(qubit)akacircuit.id(qubit)circuit.p(theta, qubit)--- Phase gate, rotate by theta.circuit.r(theta, phi, qubit)--- Rotation by theta around the cos(phi) + i*sin(phi) axis in the x-y plane.circuit.x()--- "NOT-gate", rotation by pi radians around the x-axis. Sends |0> to |1> and vice versa.circuit.y()circuit.z()circuit.s()circuit.sdg()circuit.t()circuit.tdg()circuit.u()
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circuit.cx(control_qubit, target_qubit)--- C-NOT -
circuit.ccx(control_qubit, target_qubit)--- Toffoli -
circuit.ch(control_qubit, target_qubit)--- Controlled-H -
circuit.cp(theta, control_qubit, target_qubit)--- Controlled-P -
circuit.mcp(theta, control_qubits, target_qubit)--- Multiply Controlled-P
qc.barrier() applies barrier to all qubits, with optional argument to specify qubit(s) to apply barrier to.
Defined in /circuit/quantumcircuit.py, way down at line 2643-ish.
qc.depth() returns the depth of a circuit. Can accept an optional filter function as an argument.
NOTE - qc.size() returns the total number of gate operations, which is not the same thing as the circuit depth.
Defined in /circuit/quantumcircuit.py
NOTE - qc.combine() and qc.extend() are both deprecated in favor of qc.compose() and qc.tensor()
circuit.qasm(formatted: bool = False, filename: Optional[str] = None, encoding: Optional[str] = None) -> Optional[str]
Args:
- formatted (bool): Return formatted Qasm string.
- filename (str): Save Qasm to file with name 'filename'.
- encoding (str): Optionally specify the encoding to use for the output file if
filenameis specified. By default this is set to the system's default encoding
from qiskit import QuantumCircuit, Aer
for backend in Aer.backends():
print(backend)
qc = QuantumCircuit(8)
qc.measure_all()
sim = Aer.get_backend('aer_simulator')
result = sim.run(qc_output).result()
counts = result.get_counts()
plot_histogram(counts)
- aer_simulator
- aer_simulator_statevector
- aer_simulator_density_matrix
- aer_simulator_stabilizer
- aer_simulator_matrix_product_state
- aer_simulator_extended_stabilizer
- aer_simulator_unitary
- aer_simulator_superop
- qasm_simulator
- statevector_simulator
- unitary_simulator
- pulse_simulator
Defined in /quantum_info/states/measures.py
from qiskit.quantum_info import state_fidelity
state_fidelity(state1, state2)
Expects states as statevectors or density matrices. Returns between 0 and 1, where 1 is matching states.
average_gate_fidelity() and process_fidelity() is for channels and operators.
The default backend for QuantumCircuit.draw() or qiskit.visualization.circuit_drawer() is the text backend.
Valid options are:
qc.draw("text") # ASCII art
qc.draw("mpl") # image rendered with matplotlib
qc.draw("latex") # image rendered from latex
qc.draw("latex_source") # raw latex source code for an image
Many other args, but filename is likely most useful other one (string for the filename to save image as...).
from qiskit.visualization import plot_histogram
counts = result.get_counts(circuit)
plot_histogram(counts)
Defined in /visualization/state_visualization.py, about line 180.
from qiskit.visualizations import plot_bloch_vector
plot_bloch_vector([0, 1, 0], title="some title")
plot_bloch_vector([1, 1, 1], coord_type="spherical")
Expects a three element array of coordinates--by default Cartesian ([x, y, z]).
If coord_type="spherical" is supplied, then expects [(r, theta, phi]).