For quantum computers to successfully solve real-world problems, it is necessary to tackle
the challenge of noise: the errors that occur in elementary physical components due to …

Quantum error mitigation has been proposed as a means to combat unwanted and
unavoidable errors in near-term quantum computing without the heavy resource overheads …

Numerous quantum error-mitigation protocols have been proposed, motivated by the critical
need to suppress noise effects on intermediate-scale quantum devices. Yet, their general …

Quantum computers have progressed towards outperforming classical supercomputers, but
quantum errors remain the primary obstacle. In the past few years, the field of quantum error …

We provide a polynomial-time classical algorithm for noisy quantum circuits. The algorithm
computes the expectation value of any observable for any circuit, with a small average error …

Estimating expectation values is a key subroutine in quantum algorithms. Near-term
implementations face two major challenges: a limited number of samples required to learn a …

The Heisenberg limit [(HL), with estimation error scales as 1/n] and the standard quantum
limit (SQL,∝ 1/n) are two fundamental limits in estimating an unknown parameter in n copies …

Variational quantum eigensolvers (VQEs) are leading candidates to demonstrate near-term
quantum advantage. Here, we conduct density-matrix simulations of leading gate-based …

Real photonic devices are subject to photon losses that can decohere quantum information
encoded in the system. In the absence of full fault tolerance, quantum error mitigation …

When simulating the time evolution of quantum many-body systems on a digital quantum
computer, one faces the challenges of quantum noise and of the Trotter error due to time …