activity
20152025
most citedEstimating outcome probabilities of quantum circuits using quasiprobabilities

211 citations · 548 across the 13 of their papers we have counts for

collaborators

13 papers

quant-ph2025

Classical simulation of noisy quantum circuits via locally entanglement-optimal unravelings

Simon Cichy, Paul K. Faehrmann, Lennart Bittel +2

Classical simulations of noisy quantum circuits are instrumental to our understanding of the behavior of real-world quantum systems and the identification of regimes where one expe…

quant-ph2025

Streaming quantum state purification for general mixed states

Daniel Grier, Debbie Leung, Zhi Li +2

Given multiple copies of a mixed quantum state with an unknown, nondegenerate principal eigenspace, quantum state purification is the task of recovering a quantum state that is clo…

quant-ph2024

On the Trainability and Classical Simulability of Learning Matrix Product States Variationally

Afrad Basheer, Yuan Feng, Christopher Ferrie +2

We prove that using global observables to train the matrix product state ansatz results in the vanishing of all partial derivatives, also known as barren plateaus, while using loca…

quant-ph2024★ 1 cited

Principal eigenstate classical shadows

Daniel Grier, Hakop Pashayan, Luke Schaeffer

Given many copies of an unknown quantum state , we consider the task of learning a classical description of its principal eigenstate. Namely, assuming that has an eigenstate…

quant-ph2022★ 2 cited

Non-Exponential Behaviour in Logical Randomized Benchmarking

Athena Ceasura, Pavithran Iyer, Joel J. Wallman +1

We construct a gate and time-independent noise model that results in the output of a logical randomized benchmarking protocol oscillating rather than decaying exponentially. To ill…

quant-ph2022★ 15 cited

Sample-optimal classical shadows for pure states

Daniel Grier, Hakop Pashayan, Luke Schaeffer

We consider the classical shadows task for pure states in the setting of both joint and independent measurements. The task is to measure few copies of an unknown pure state in…

quant-ph2022★ 58 cited

Shallow shadows: Expectation estimation using low-depth random Clifford circuits

Christian Bertoni, Jonas Haferkamp, Marcel Hinsche +3

We provide practical and powerful schemes for learning many properties of an unknown n-qubit quantum state using a sparing number of copies of the state. Specifically, we present a…

quant-ph2021★ 48 cited

Improved upper bounds on the stabilizer rank of magic states

Hammam Qassim, Hakop Pashayan, David Gosset

In this work we improve the runtime of recent classical algorithms for strong simulation of quantum circuits composed of Clifford and T gates. The improvement is obtained by establ…

quant-ph2021★ 35 cited

Fast estimation of outcome probabilities for quantum circuits

Hakop Pashayan, Oliver Reardon-Smith, Kamil Korzekwa +1

We present two classical algorithms for the simulation of universal quantum circuits on qubits constructed from instances of Clifford gates and arbitrary-angle -rota…

quant-ph2020★ 121 cited

Quantifying quantum speedups: improved classical simulation from tighter magic monotones

James R. Seddon, Bartosz Regula, Hakop Pashayan +2

Consumption of magic states promotes the stabilizer model of computation to universal quantum computation. Here, we propose three different classical algorithms for simulating such…

quant-ph2017★ 49 cited

From estimation of quantum probabilities to simulation of quantum circuits

Hakop Pashayan, Stephen D. Bartlett, David Gross

Investigating the classical simulability of quantum circuits provides a promising avenue towards understanding the computational power of quantum systems. Whether a class of quantu…

quant-ph2016★ 8 cited

Contextuality under weak assumptions

Andrew W. Simmons, Joel J. Wallman, Hakop Pashayan +2

The presence of contextuality in quantum theory was first highlighted by Bell, Kochen and Specker, who discovered that for quantum systems of three or more dimensions, measurements…

quant-ph2015★ 211 cited

Estimating outcome probabilities of quantum circuits using quasiprobabilities

Hakop Pashayan, Joel J. Wallman, Stephen D. Bartlett

We present a method for estimating the probabilities of outcomes of a quantum circuit using Monte Carlo sampling techniques applied to a quasiprobability representation. Our estima…