IBM A1000-128 Practice Exam 2025: Latest Questions

A learner says, "If I measure one qubit from an entangled pair, I can control the outcome of the other qubit instantly and send a message faster than light." Which statement best corrects this misunderstanding?

In the computational basis, what is the most accurate interpretation of measuring a qubit prepared in the state |+> = (|0> + |1>)/sqrt(2)?

A developer builds a Bell-state circuit: apply H to qubit 0, then CNOT with control qubit 0 and target qubit 1, then measure both in the computational basis. In an ideal simulator, which measurement outcomes should they expect most often?

A team wants to run a circuit on real IBM quantum hardware but notices compilation introduces SWAP gates that increase error. Which best practice most directly helps reduce added SWAPs?

A researcher wants to estimate the expectation value of an observable by running the same circuit many times and computing an average from measurement results. Which term best describes the purpose of increasing the number of shots?

A circuit is executed on hardware and the results differ significantly from an ideal simulator. The circuit contains many two-qubit gates. Which explanation is most likely?

A developer uses Qiskit and wants to see how their circuit is rewritten to match a specific device’s supported gate set and connectivity. Which step provides this device-specific rewriting?

A product team is evaluating quantum for optimization. They have a problem of selecting a set of items under constraints (a combinatorial optimization problem). Which approach is most aligned with near-term quantum use cases on NISQ devices?

A user runs a circuit with mid-circuit measurements and conditional operations, but the job fails on a chosen backend. What is the most likely cause and best next step?

A team wants to compare two transpilation strategies for the same algorithm on a specific hardware backend. They notice Strategy 1 has fewer total gates but a longer circuit depth than Strategy 2. For NISQ hardware, which metric is typically most critical to reduce overall error, assuming similar gate fidelities?

A developer is new to quantum computing and asks what a measurement does to a qubit state in an ideal circuit. Which statement best describes the effect of measurement?

A team is writing their first Qiskit program and wants to run on a real IBM Quantum device after local testing. Which approach is a best practice for moving from simulator to hardware?

A researcher describes a system as 'using n qubits.' In terms of the size of the state vector for a pure state, what is correct?

A circuit uses an ancilla qubit to compute a parity check and then needs the ancilla returned to |0⟩ before the circuit ends. Which technique is most appropriate?

A user runs a circuit on a simulator and on real hardware. The simulator results match theory, but hardware results are biased and less accurate. Which is the most likely reason?

A circuit that creates a Bell state unexpectedly shows outcomes 00, 01, 10, and 11 with roughly equal probability on a real device. A code review shows the CNOT was applied, but the Hadamard was placed on the wrong qubit. What is the most likely issue?

A team wants to compare two circuit designs on a specific IBM Quantum backend and choose the one likely to yield higher fidelity. Which metric is generally the best proxy to compare before execution?

A product team is exploring near-term quantum advantage for optimization. They have a quadratic unconstrained binary optimization (QUBO) problem. Which approach aligns best with common near-term IBM Quantum use patterns?

A developer needs to mitigate measurement (readout) error on hardware runs without changing the algorithm’s unitary portion. Which technique is most appropriate?

A researcher is implementing phase estimation concepts but wants a foundational understanding: why does applying a controlled-U operation with an eigenstate |ψ⟩ of U enable phase information to be extracted in the control register?

A learner is told that measuring the first qubit of a 2-qubit Bell state will also determine the second qubit’s measurement outcome (in the same basis). Which statement best explains why?

You are building a circuit where two quantum states must interfere so that some measurement outcomes become more likely and others are suppressed. Which concept most directly enables this effect?

A developer runs a Qiskit circuit with mid-circuit measurement and conditional operations, but the results are inconsistent with expectations. Which is the most likely issue to check first?

A team wants to run the same parameterized circuit many times with different parameter values to reduce compilation overhead and improve throughput. Which approach is the best practice on the IBM Quantum platform using Qiskit?

A researcher is evaluating whether a near-term quantum approach is appropriate for a real-world optimization problem (e.g., scheduling). They have limited qubits and expect significant noise. Which statement is the most accurate guidance?