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Large-scale variational quantum algorithms are widely recognized as a potential pathway to achieve practical quantum advantages. However, the presence of quantum noise might suppress and undermine these advantages, which blurs the…

Quantum Physics · Physics 2024-09-20 Yuguo Shao , Fuchuan Wei , Song Cheng , Zhengwei Liu

State-of-the-art quantum computers can only reliably execute circuits with limited qubit numbers and computational depth. This severely reduces the scope of algorithms that can be run. While numerous techniques have been invented to exploit…

Quantum Physics · Physics 2023-12-25 Adrián Pérez-Salinas , Radoica Draškić , Jordi Tura , Vedran Dunjko

The contrast of an image can be degraded by the presence of background light and sensor noise. To overcome this degradation, quantum illumination protocols have been theorised (Science 321 (2008), Physics Review Letters 101 (2008)) that…

Quantum Physics · Physics 2021-09-21 Thomas Gregory , Paul-Antoine Moreau , Ermes Toninelli , Miles J. Padgett

We present a deep neural network to reduce coherent noise in three-dimensional quantitative phase imaging. Inspired by the cycle generative adversarial network, the denoising network was trained to learn a transform between two image…

Correlated photon pairs, carrying strong quantum correlations, have been harnessed to bring quantum advantages to various fields from biological imaging to range finding. Such inherent non-classical properties support extracting more valid…

Quantum Physics · Physics 2020-06-18 Zhan-Ming Li , Shi-Bao Wu , Jun Gao , Heng Zhou , Zeng-Quan Yan , Ruo-Jing Ren , Si-Yuan Yin , Xian-Min Jin

One of the core research questions in the theory of quantum computing is to find out to what precise extent the classical simulation of a noisy quantum circuits is possible and where potential quantum advantages can set in. In this work, we…

Quantum Physics · Physics 2026-01-09 Janek Denzler , Jose Carrasco , Jens Eisert , Tommaso Guaita

We consider the problem of decoding corrupted error correcting codes with NC$^0[\oplus]$ circuits in the classical and quantum settings. We show that any such classical circuit can correctly recover only a vanishingly small fraction of…

Computational Complexity · Computer Science 2024-01-25 Jop Briët , Harry Buhrman , Davi Castro-Silva , Niels M. P. Neumann

We are concerned with numerical simulations of quantum optical circuits under certain realistic conditions, specifically that photon quantum states are not perfectly indistinguishable. The partial photon distinguishability presents a…

Quantum Physics · Physics 2023-07-14 Javier Osca , Jiri Vala

Quantum advantage requires overcoming noise-induced degradation of quantum systems. Conventional methods for reducing noise such as error mitigation face scalability issues in deep circuits. Specifically, noise hampers the extraction of…

Quantum Physics · Physics 2023-12-05 Yonglong Ding , Ruyu Yang

Quantum mechanics promises computational powers beyond the reach of classical computers. Current technology is on the brink of an experimental demonstration of the superior power of quantum computation compared to classical devices. For…

Quantum Physics · Physics 2019-04-02 Jelmer Renema , Valery Shchesnovich , Raul Garcia-Patron

Finding solid and practical quantum advantages via noisy quantum devices without error correction is a critical but challenging problem. Conversely, comprehending the fundamental limitations of the state-of-the-art is equally crucial. In…

Quantum Physics · Physics 2026-03-25 Yuxuan Yan , Zhenyu Du , Junjie Chen , Xiongfeng Ma

Noise is often regarded as anathema to quantum computation, but in some settings it can be an unlikely ally. We consider the problem of learning the class of $n$-bit parity functions by making queries to a quantum example oracle. In the…

Quantum Physics · Physics 2015-08-05 Andrew W. Cross , Graeme Smith , John A. Smolin

Noise detrimentally affects quantum computations so that they not only become less accurate but also easier to simulate classically as systems scale up. We construct a classical simulation algorithm, LOWESA (low weight efficient simulation…

Quantum Physics · Physics 2023-06-09 Enrico Fontana , Manuel S. Rudolph , Ross Duncan , Ivan Rungger , Cristina Cîrstoiu

Analyzing the impact of noise is of fundamental importance to understand the advantages provided by quantum systems. While the classical simulability of noisy discrete-variable systems is increasingly well understood, noisy bosonic circuits…

Quantum Physics · Physics 2026-01-12 Varun Upreti , Ulysse Chabaud , Zoë Holmes , Armando Angrisani

Loss is inevitable for the optical system due to absorption of materials, scattering caused by the defects and surface roughness. In quantum optical circuits, the loss can not only reduce the intensity of signal, but also affect the…

Optics · Physics 2017-11-22 Ming Li , Chang-Ling Zou , Guang-Can Guo , Xi-Feng Ren

Long-lived optical quantum memories are of great importance for scalable distribution of entanglement over remote networks (e.g. quantum repeaters). Long-lived storage generally relies on storing the optical states as spin excitations since…

Quantum Physics · Physics 2017-08-15 Emmanuel Zambrini Cruzeiro , Florian Fröwis , Nuala Timoney , Mikael Afzelius

In a distributed quantum computer scalability is accomplished by networking together many elementary nodes. Typically the network is optical and inter-node entanglement involves photon detection. In complex networks the entanglement…

Quantum Physics · Physics 2013-05-29 Yuichiro Matsuzaki , Simon C. Benjamin , Joseph Fitzsimons

Near term quantum computers with a high quantity (around 50) and quality (around 0.995 fidelity for two-qubit gates) of qubits will approximately sample from certain probability distributions beyond the capabilities of known classical…

Quantum Physics · Physics 2018-01-23 Sergio Boixo , Sergei V. Isakov , Vadim N. Smelyanskiy , Hartmut Neven

In the literature, the study of electron transport in quantum devices is mainly devoted to DC properties. The fluctuations of the electrical current around these DC values, the so-called quantum noise, are much less analyzed. The…

Quantum Physics · Physics 2015-03-11 Damiano Marian , Enrique Colomés , Zhen Zhan , Xavier Oriols

Quantum circuits with local particle number conservation (LPNC) restrict the quantum computation to a subspace of the Hilbert space of the qubit register. In a noiseless or fault-tolerant quantum computation, such quantities are preserved.…

Quantum Physics · Physics 2021-04-21 Michael Streif , Martin Leib , Filip Wudarski , Eleanor Rieffel , Zhihui Wang