paper / kristantemme / Apr 3
Temme and Wocjan introduce a framework for quantizing classical Markov chains by leveraging the coupling method — a standard tool for proving rapid mixing — to construct a completely positive and trace preserving (CPTP) quantum map. This map has a unique fixed point corresponding to the "qsample," the quantum analog of the classical stationary distribution. Crucially, the convergence rate of the quantum map is directly governed by the coupling time of the underlying classical Markov chain coupling, establishing a tight operational link between classical mixing analysis and quantum state preparation complexity.
quantum-computingmarkov-chainsquantum-samplingmathematical-physicsquantum-algorithmsmixing-times
“A CPTP quantum map can be constructed from a classical Markov chain coupling (e.g., a grand coupling) that has the qsample of the stationary distribution as its unique fixed point.”
paper / kristantemme / Oct 11
This paper extends Probabilistic Error Cancellation (PEC) to dynamic quantum circuits that incorporate mid-circuit measurements and classically-controlled operations. The authors introduce a sparse Pauli-Lindblad noise model to account for measurement-based operations and non-local measurement crosstalk. This advancement is crucial for near-term dynamic circuit applications by providing enhanced error mitigation and monitoring capabilities.
quantum-physicsquantum-circuitserror-mitigationmeasurement-based-quantum-computationsparse-pauli-lindblad-noise-modelsuperconducting-processors
“Probabilistic Error Cancellation (PEC) has been extended to dynamic quantum circuits.”
paper / kristantemme / Jul 6
Quantum computing presents a potential paradigm shift for high-energy physics, offering exponential speedups for complex simulations currently intractable with classical methods. This roadmap, a collaboration between CERN, DESY, and IBM, evaluates the current state of quantum computing in high-energy physics. It identifies key theoretical and experimental applications and provides resource estimations for error-mitigated quantum computing, aligning with the IBM 100 x 100 challenge.
quantum-computinghigh-energy-physicsquantum-advantagenumerical-simulationsquantum-hardwarecernibm
“Quantum computing offers significant, potentially exponential, speedups for numerical simulations in natural sciences.”
paper / kristantemme / Jun 30
This paper evaluates a quantum error mitigation protocol applied to IBM Eagle processor circuits. It highlights the challenges of benchmarking quantum protocols beyond easily verifiable regimes, noting that different classical simulation methods yield discrepancies up to 20%. This uncertainty rivals experimental error bars, suggesting a need for circuit modifications to challenge specific classical methods and improve benchmarking accuracy.
quantum-physicsquantum-computingquantum-circuitsquantum-error-mitigationquantum-benchmarkingzero-noise-extrapolation
“A quantum error mitigation protocol was applied to IBM Eagle quantum processor circuits with up to 127 qubits and 60 CNOT layers.”
paper / kristantemme / Mar 11
This paper introduces novel estimators for Probabilistic Error Cancellation (PEC) and Zero-Noise Extrapolation (ZNE), two leading error mitigation techniques in quantum computing. By incorporating light-cone arguments, the proposed PEC estimator significantly reduces sampling overhead, while the ZNE error bound offers a more precise understanding of residual bias. These advancements enhance the efficiency and accuracy of quantum expectation value estimations, particularly for local observables.
quantum-physicserror-mitigationquantum-circuitsprobabilistic-error-cancellationzero-noise-extrapolationlocal-observables
“A new estimator for Probabilistic Error Cancellation (PEC) reduces sampling overhead.”