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Related papers: Quantum Noise and Superluminal Propagation

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We propose a method for quantum noise extraction from the interference of laser pulses with random phase. Our technique is based on the calculation of a parameter, which we called the quantum reduction factor, and which allows determining…

Overparametrization is one of the most surprising and notorious phenomena in machine learning. Recently, there have been several efforts to study if, and how, Quantum Neural Networks (QNNs) acting in the absence of hardware noise can be…

Quantum Physics · Physics 2024-03-19 Diego García-Martín , Martin Larocca , M. Cerezo

We analytically study the linear propagation of arbitrarily shaped light-pulses through an absorbing medium with a narrow transparency-window or through a resonant amplifying medium. We point out that, under certain general conditions, the…

Optics · Physics 2012-09-14 Bruno Macke , Bernard Ségard

Suprecontinuum (SC) light contains complex spectral noise structure and its accurate characterization is important for fundamental understanding of its physics as well as for its applications. Several experimental and theoretical noise…

We treat a model based upon nonlinear optics for the semiclassical gravitational effects of quantum fields upon light propagation. Our model uses a nonlinear material with a nonzero third order polarizability. Here a probe light pulse…

General Relativity and Quantum Cosmology · Physics 2014-07-23 C. H. G. Bessa , V. A. De Lorenci , L. H. Ford

The effect of an ac perturbation on the shot noise of a fractional quantum Hall fluid is studied at finite temperature. For a normal metal, it is known that the zero-frequency noise derivative exhibits steps as a function of bias voltage.…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Adeline Crepieux , Pierre Devillard , Thierry Martin

Superradiance is the archetypical collective phenomenon where radiation is amplified by the coherence of emitters. It plays a prominent role in optics, where it enables the design of lasers with substantially reduced linewidths, quantum…

A strong light pulse propagating in a nonlinear medium causes an effective change in the local refractive index. With a suitable tuning of the pulse velocity, the leading and trailing edge of the pulse were predicted to behave as analogue…

Optics · Physics 2012-08-07 Stefano Finazzi , Iacopo Carusotto

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

When a coherent electromagnetic wave passes through a beam splitter (BS), it is divided equally into two parts. However, the quantum noise associated with the resulting coherent states, despite being reduced in amplitude by half, remains…

Quantum Physics · Physics 2026-05-04 Sun-Hyun Youn

We investigate how distinguishability of a "noise" particle degrades interference of the "signal" particle. The signal, represented by an equatorial state of a photonic qubit, is mixed with noise, represented by another photonic qubit, via…

Quantum Physics · Physics 2013-08-16 Miroslav Gavenda , Lucie Celechovska , Jan Soubusta , Miloslav Dusek , Radim Filip

We discuss the propagation of laser radiation through a medium of quantum prepared {\Lambda}-type atoms in order to enhance the insight into the physics of QS-PT generator suggested in Phys. Rev. A 80, 035801 (2009). We obtain analytical…

Quantum Physics · Physics 2015-05-28 Gevorg Muradyan , Atom Zh. Muradyan

In many quantum architectures the solid-state qubits, such as quantum dots or color centers, are interfaced via emitted photons. However, the frequency of photons emitted by solid-state systems exhibits slow uncontrollable fluctuations over…

Quantum Physics · Physics 2016-01-27 H. F. Fotso , A. E. Feiguin , D. D. Awschalom , V. V. Dobrovitski

In ultrabroadband terahertz electro-optic sampling, spectral filtering of the gate pulse can strongly reduce the quantum noise while the signal level is only weakly affected. The concept is tested for phase-matched electro-optic detection…

Optics · Physics 2016-04-25 Michael Porer , Jean-Michel Ménard , Rupert Huber

The propagation of short lightpulses in waveguiding structures with optical feedback, in our case optical microresonators, has been studied theoretically and experimentally. It appears that, dependent on the measurement set-up, ballistic…

Though both theoretical and experimental investigations have revealed the superluminal behavior of evanescent electromagnetic waves, there are many disputes about the physical meaning and validity of such superluminal phenomenon, which is…

Quantum Physics · Physics 2015-06-26 Zhi-Yong Wang , Cai-Dong Xiong

We demonstrate that significant effects in the "superluminal propagation"of light-pulses cannot be observed without involving systems whose gain explodes outside the pulse spectrum. We explicitly determine the minimum norm of the gain to…

Optics · Physics 2016-08-16 Bruno Macke , Bernard Ségard , Franck Wielonsky

Laser noise is a decisive limiting factor in high precision spectroscopy of narrow lines using atomic ensembles. In an idealized Doppler and differential light shift free magic wavelength lattice configuration, it remains as one distinct…

Quantum Physics · Physics 2017-03-20 David Plankensteiner , Johannes Schachenmayer , Helmut Ritsch , Claudiu Genes

At nanohertz frequencies gravitational waves (GWs) cause variations in time-of-arrival of pulsar signals potentially measurable via precision timing observations. Here we compute very-low-frequency GW sensitivity constrained by…

General Relativity and Quantum Cosmology · Physics 2015-03-17 Fredrick A. Jenet , J. W. Armstrong , Massimo Tinto

We theoretically investigate the influence of designed pulse sequences in restoring quantum coherence lost due to background noise in superconducting qubits. We consider both 1/f noise and Random Telegraph Noise, and show that the qubit…

Mesoscale and Nanoscale Physics · Physics 2008-06-19 L. Cywinski , R. M. Lutchyn , C. P. Nave , S. Das Sarma