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An important challenge in quantum science is to fully understand the efficiency of energy flow in networks. Here we present a simple and intuitive explanation for the intriguing observation that optimally efficient networks are not purely…

Quantum Physics · Physics 2015-03-24 Ying Li , Filippo Caruso , Erik Gauger , Simon C. Benjamin

The sensitivity of classical and quantum sensing is impaired in a noisy environment. Thus, one of the main challenges facing sensing protocols is to reduce the noise while preserving the signal. State of the art quantum sensing protocols…

Optics · Physics 2016-07-18 L. Cohen , Y. Pilnyak , D. Istrati , A. Retzker , H. S. Eisenberg

Photon loss is destructive to the performance of quantum photonic devices and therefore suppressing the effects of photon loss is paramount to photonic quantum technologies. We present two schemes to mitigate the effects of photon loss for…

Quantum Physics · Physics 2021-05-05 Daiqin Su , Robert Israel , Kunal Sharma , Haoyu Qi , Ish Dhand , Kamil Brádler

We investigate (a) spontaneous Raman scattering of classical signals in long optical fiber links leading to significant Raman noise in quantum channels propagating in the same fiber and (b) impact of chromatic dispersion on the performance…

Quantum Physics · Physics 2017-12-19 Michal Mlejnek , Nikolay A. Kaliteevskiy , Dan A. Nolan

To understand quantum optics experiments, we must perform calculations that consider the principal sources of noise, such as losses, spectral impurity and partial distinguishability. In both discrete and continuous variable systems, these…

Quantum Physics · Physics 2025-08-15 Jacob F. F. Bulmer , Javier Martínez-Cifuentes , Bryn A. Bell , Nicolás Quesada

In this paper we do a detailed numerical investigation of the fault-tolerant threshold for optical cluster-state quantum computation. Our noise model allows both photon loss and depolarizing noise, as a general proxy for all types of local…

Quantum Physics · Physics 2009-11-13 Christopher M. Dawson , Henry L. Haselgrove , Michael A. Nielsen

Far-field optical imaging inevitably involves low-pass spatial filtering, limiting the resolution. Moreover, conventional imaging suppresses high spatial frequency components close to the cutoff, making them invisible under noise,…

Quantum Physics · Physics 2026-05-08 Li Gong , Aonan Zhang , Madhura Ghosh Dastidar , Alexander Duplinskii , A. I. Lvovsky

Noise in quantum systems is a major obstacle to implementing many quantum algorithms on large quantum circuits. In this work, we study the effects of noise on the Rademacher complexity of quantum circuits, which is a measure of statistical…

Quantum Physics · Physics 2021-03-05 Kaifeng Bu , Dax Enshan Koh , Lu Li , Qingxian Luo , Yaobo Zhang

The complexity of simulating quantum many-body dynamics, or quantum computations, in the Heisenberg picture is governed by the scrambling of initially simple operators into superpositions of exponentially many Pauli strings. The…

Quantum Physics · Physics 2026-05-20 Neil Dowling , Xhek Turkeshi , Jacopo De Nardis , Guglielmo Lami

It is known that if the quantum gates in a proposed quantum computer are so noisy that they are incapable of generating entanglement, then the device can be efficiently simulated classically. If the measurements and single particle…

Quantum Physics · Physics 2012-01-04 N. Ratanje , S. Virmani

Imaging with quantum states of light promises advantages over classical approaches in terms of resolution, signal-to-noise ratio and sensitivity. However, quantum detectors are particularly sensitive sources of classical noise that can…

Quantum Physics · Physics 2019-07-16 Hugo Defienne , Matthew Reichert , Jason W Fleischer , Daniele Faccio

We analyze the complexity of classically simulating continuous-time dynamics of locally interacting quantum spin systems with a constant rate of entanglement breaking noise. We prove that a polynomial time classical algorithm can be used to…

Quantum Physics · Physics 2022-11-11 Rahul Trivedi , J. Ignacio Cirac

The speed-up provided by quantum algorithms with respect to their classical counterparts is at the origin of scientific interest in quantum computation. However, the fundamental reasons for such a speed-up are not yet completely understood…

Quantum Physics · Physics 2007-05-23 C. Di Franco , M. Paternostro , M. S. Kim

The search for new, application-specific quantum computers designed to outperform any classical computer is driven by the ending of Moore's law and the quantum advantages potentially obtainable. Photonic networks are promising examples,…

Quantum Physics · Physics 2018-04-10 Bogdan Opanchuk , Laura Rosales-Zarate , Margaret D Reid , Peter D Drummond

We investigate the correspondence between classical noise and quantum environments. Although it has been known that the classical noise can be mapped to the quantum environments only for pure dephasing and infinite-temperature dissipation…

Quantum Physics · Physics 2024-12-31 Jiarui Zeng , Guo-Hao Xu , Weijie Huang , Yao Yao

A defining feature in the field of quantum computing is the potential of a quantum device to outperform its classical counterpart for a specific computational task. By now, several proposals exist showing that certain sampling problems can…

Quantum Physics · Physics 2020-09-23 Rawad Mezher , Joe Ghalbouni , Joseph Dgheim , Damian Markham

We present a computational problem with the following properties: (i) Every instance can be solved with near-certainty by a constant-depth quantum circuit using only nearest-neighbor gates in 3D even when its implementation is corrupted by…

Quantum Physics · Physics 2023-12-15 Libor Caha , Xavier Coiteux-Roy , Robert Koenig

Magic states are essential for universal quantum computation and are widely viewed as a key source of quantum advantage, yet in realistic devices they are inevitably noisy. In this work, we characterize how noise on injected magic resources…

Quantum Physics · Physics 2026-01-21 Jiwon Heo , Sojeong Park , Changhun Oh

We present conditions for the efficient simulation of a broad class of optical quantum circuits on a classical machine: this class includes unitary transformations, amplification, noise, and measurements. Various proposed schemes for…

Quantum Physics · Physics 2007-05-23 Stephen D. Bartlett , Barry C. Sanders

We present shadow spectroscopy as a simulator-agnostic quantum algorithm for estimating energy gaps using very few circuit repetitions (shots) and no extra resources (ancilla qubits) beyond performing time evolution and measurements. The…

Quantum Physics · Physics 2025-04-10 Hans Hon Sang Chan , Richard Meister , Matthew L. Goh , Bálint Koczor