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Suppose a two-dimensional dynamical system has a stable attractor that is surrounded by an unstable limit cycle. If the system is additively perturbed by white noise, the rate of escape through the limit cycle will fall off exponentially as…

Condensed Matter · Physics 2007-05-23 Robert S. Maier , Daniel L. Stein

Current quantum noise can be pictured as a sum over transitions through which the electronic system exchanges energy with its environment. We formulate this picture and use it to show which type of current correlators are measurable, and in…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 U. Gavish , Y. Imry , Y. Levinson

Linear quantum amplifiers are indispensable tools for quantum technologies, yet their performance is fundamentally limited by quantum noise, precluding any signal-to-noise ratio (SNR) enhancement unless supplemented by post-selection or…

Quantum Physics · Physics 2026-03-13 Ya-Long Ren , Rong-Teng Cao , Sheng-Li Ma , Ren Zhang , Fu-Li Li , Franco Nori , Peng-Bo Li

Quantum mechanics can strongly influence the noise properties of mesoscopic devices. To probe this effect we have measured the current fluctuations at high-frequency (5-90 GHz) using a superconductor-insulator-superconductor tunnel junction…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. Deblock , E. Onac , L. Gurevich , L. P. Kouwenhoven

We consider a quantum mechanical system to model the effect of quantum fields on the evolution of the early universe. The system consists of an inverted oscillator bilinearly coupled to a set of harmonic oscillators. We point out that the…

General Relativity and Quantum Cosmology · Physics 2025-09-11 Ezequiel Lozano , Francisco D. Mazzitelli

We present a formalism that accounts for the evolution of quantum states of travelling light pulses incident on and emanating from a local quantum scatterer such as an atom or a cavity. We assume non-dispersive asymptotic propagation of the…

Quantum Physics · Physics 2019-09-25 Alexander Holm Kiilerich , Klaus Mølmer

All quantum systems are subject to noise from the environment or external controls. This noise is a major obstacle to the realization of quantum technology. For example, noise limits the fidelity of quantum gates. Employing optimal control…

Quantum Physics · Physics 2024-09-25 Aviv Aroch , Ronnie Kosloff , Shimshon Kallush

A theory is developed for the emission noise at frequency $\nu$ in a quantum dot in the presence of Coulomb interactions and asymmetric couplings to the reservoirs. We give an analytical expression for the noise in terms of the various…

Mesoscale and Nanoscale Physics · Physics 2018-03-15 A. Crépieux , S. Sahoo , T. Q. Duong , R. Zamoum , M. Lavagna

Realizing the promise of quantum information processing remains a daunting task, given the omnipresence of noise and error. Adapting noise-resilient classical computing modalities to quantum mechanics may be a viable path towards near-term…

Quantum Physics · Physics 2021-02-03 L. C. G. Govia , G. J. Ribeill , G. E. Rowlands , H. K. Krovi , T. A. Ohki

The influence of outside quantum noises on the amplification of weak measurements is investigated. Three typical quantum noises are discussed. The maximum values of the pointer's shifts decrease sharply with the strength of the depolarizing…

Quantum Physics · Physics 2015-05-11 Xuanmin Zhu , Yu-Xiang Zhang

Characterization and suppression of noise are essential for the control of harmonic oscillators in the quantum regime. We measure the noise spectrum of a quantum harmonic oscillator from low frequency to near the oscillator resonance by…

Electrical engineers and physicists are naturally very interested in noise in circuits, amplifiers and detectors. With the advent of quantum computation and other high frequency electronics operating at low temperatures, we have entered a…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 R. J. Schoelkopf , A. A. Clerk , S. M. Girvin , K. W. Lehnert , M. H. Devoret

Dual to the usual noisy channel coding problem, where a noisy (classical or quantum) channel is used to simulate a noiseless one, reverse Shannon theorems concern the use of noiseless channels to simulate noisy ones, and more generally the…

Quantum Physics · Physics 2014-07-22 Charles H. Bennett , Igor Devetak , Aram W. Harrow , Peter W. Shor , Andreas Winter

Usual scenarios of fault-tolerant computation are concerned with the fault-tolerant realization of quantum algorithms that compute classical functions, such as Shor's algorithm for factoring. In particular, this means that input and output…

Quantum Physics · Physics 2025-12-03 Matthias Christandl , Omar Fawzi , Ashutosh Goswami

Amplification plays a key role in classical communication protocols, where it compensates the unavoidable loss of the signal. However, when we enter the quantum domain this approach starts being problematic as the standard kinds of…

Quantum Physics · Physics 2014-07-30 Petr Marek , Radim Filip

The use of distributed amplifiers may have some potential advantages for the transmission of quantum information through optical fibers. In addition to the quantum noise introduced by the amplifiers, entanglement between atoms in the…

Quantum Physics · Physics 2015-11-26 J. D. Franson , B. T. Kirby

The two-way capacities of quantum channels determine the ultimate entanglement and secret-key distribution rates achievable by two distant parties that are connected by a noisy transmission line, in absence of quantum repeaters. Since…

Quantum Physics · Physics 2025-01-27 Francesco Anna Mele , Ludovico Lami , Vittorio Giovannetti

It is shown that coherence resonance, a phenomenon in which regularity of noise-induced oscillations in nonlinear excitable systems is maximized at a certain optimal noise intensity, can be observed in quantum dissipative systems. We…

Adaptation and Self-Organizing Systems · Physics 2021-04-12 Yuzuru Kato , Hiroya Nakao

We prove new upper bounds on the tolerable level of noise in a quantum circuit. We consider circuits consisting of unitary k-qubit gates each of whose input wires is subject to depolarizing noise of strength p, as well as arbitrary…

Quantum Physics · Physics 2008-02-12 Julia Kempe , Oded Regev , Falk Unger , Ronald de Wolf

Even though measurement results obtained in the real world are generally both noisy and continuous, quantum measurement theory tends to emphasize the ideal limit of perfect precision and quantized measurement results. In this article, a…

Quantum Physics · Physics 2008-12-18 Holger F. Hofmann