Final mission

Run your first circuit on a real quantum computer

Move through four scientific steps: predict, simulate, use IBM Quantum Composer with supervision, and explain the comparison without overstating the evidence.

Adult or teacher supervision requiredIBM may require an external account and may offer paid plans. A supervising adult should review account, privacy and cost information before sign-in or hardware submission. Pi Leo Academy never asks for or stores IBM passwords, API keys, tokens, cloud credentials or payment details.

Part A · Predict

What pattern should H produce?

Prepare q0 in the |0⟩ reference state.
Apply H.
Measure q0.
Repeat with 1,000 or 1,024 fresh shots.

Choose your prediction All results will be 0. Counts will usually be near half 0 and half 1. Counts must be exactly equal.

Why?

Part B · Test in the Pi Leo simulator

Run the same preparation many times

The lab below is an ideal mathematical simulator. Counts will generally be near half 0 and half 1, but a finite sample is not guaranteed to be exactly equal.

Built-in circuit lab

Build from left to right

Ideal simulator

Choose the number of qubits, add instructions with the buttons, then predict before you run. Every drag action has a keyboard button alternative.

Qubits Target

No instructions yet.

Your prediction before running

Shots Sampling Display

Initial state: every qubit is prepared as |0⟩.

Circuit results

Simulator

Exact probabilities and sampled results
Result	Exact chance	Count	Sample percent
0	100%	—	—

Run the simulator to create a text summary of the chart.

Bit-order legend

Pi Leo labels wires q0, q1 and q2 from top to bottom. In displayed result strings, the highest-numbered bit is written on the left, so a two-qubit result is shown as q1q0. This matches the convention used in the Pi Leo simulator and common Qiskit count strings.

Gate definitions

X: Exchanges the |0⟩ and |1⟩ reference states in these examples.
H: Changes the state direction and can create equal 0/1 measurement probabilities from |0⟩.
Z: Changes relative phase. Its effect may appear only after a later analysing gate.
CX: Applies X to a target when its control is in the |1⟩ reference state.
Measurement: Produces a classical bit result.

Static fallback: circuits begin with every qubit at |0⟩. Read gates left to right. X changes |0⟩ to |1⟩; H on |0⟩ gives 50% 0 and 50% 1 when measured; H on q0 followed by CX from q0 to q1 gives 00 and 11 with equal ideal probabilities.

Optional: build the two-qubit Bell circuit

Choose two qubits. Add H to q0, then CX with q0 as control and q1 as target, then measure. The ideal simulator predicts only 00 and 11, each with probability one half.

Bit-order legend

Part C · IBM Quantum Composer

Use the graphical workflow first

Workflow checked against official IBM Quantum documentation on 15 August 2026.

External service notice

IBM’s interface, access rules, account requirements, and plan limits may change. These steps were last checked on 15 August 2026. Hardware access is not promised to remain free; review the plan attached to the selected IBM Quantum Compute Service instance before submitting.

1
Open IBM Quantum Composer in a new tab.
Use IBM’s graphical circuit tool. You can explore small simulated visualisations before signing in.
2
Build the circuit visually.
Use one wire, place H on q0, then add measurement. Check that time runs from left to right.
3
Run a simulator first.
Review the simulated histogram and compare it with your Part A prediction. A simulator is ordinary classical software, not a QPU.
4
Sign in only for physical hardware.
With your supervising adult or teacher, sign in to IBM Quantum Platform and review the instance and plan that control access.
5
Choose an available permitted QPU.
Select Run circuit, review the instance, QPU and shot settings, and avoid relying on a saved device name because the available fleet changes.
6
Submit and record the job identifier.
Use the button labelled for the selected QPU. IBM normally sends an unspecified run to a least-busy available QPU. The Workloads area shows queue and job status.
7
Retrieve and compare the result.
When the job finishes, review its histogram, original circuit and transpiled circuit. Record the device and execution details shown by IBM.

Open IBM Quantum Composer

This link opens an external IBM site. Pi Leo Academy does not receive your IBM account details, circuit, job or result.

Show me the codeOptional Python extension for older students

This example follows the current IBM Quantum Platform, Qiskit Runtime and Sampler V2 workflow. Run it only in a trusted local environment configured directly with IBM—not in Pi Leo Academy and never with a token pasted into this page.

from qiskit import QuantumCircuit
from qiskit.transpiler import generate_preset_pass_manager
from qiskit_ibm_runtime import QiskitRuntimeService, SamplerV2 as Sampler

# Uses credentials configured in your own trusted environment.
service = QiskitRuntimeService()
backend = service.least_busy(
    operational=True,
    simulator=False,
    min_num_qubits=1,
)

circuit = QuantumCircuit(1)
circuit.h(0)
circuit.measure_all()

pass_manager = generate_preset_pass_manager(
    backend=backend,
    optimization_level=1,
)
isa_circuit = pass_manager.run(circuit)

sampler = Sampler(mode=backend)
job = sampler.run([isa_circuit], shots=1024)
counts = job.result()[0].data.meas.get_counts()
print("Job:", job.job_id())
print("Counts:", counts)

Verification: checked 15 August 2026 against IBM’s SamplerV2 and transpilation documentation. A Python 3.11 smoke test with Qiskit 2.5.2 and qiskit-ibm-runtime 0.47.0 successfully constructed the circuit, transpiled it against IBM’s verified FakeSherbrooke teaching target and instantiated SamplerV2. No live job was submitted because this repository never stores an IBM credential.

Part D · Think like a scientist

Record enough detail for someone else to understand your comparison

Official workflow sources

Accessed and checked 15 August 2026. External pages may change after that date.