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Related papers: Geometric Quantum Noise of Spin

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We study quantum noise in a nonequilibrium, periodically driven, open system attached to static leads. Using a Floquet Green's function formalism we show, both analytically and numerically, that local voltage noise spectra can detect the…

Mesoscale and Nanoscale Physics · Physics 2018-08-01 M. Rodriguez-Vega , H. A. Fertig , B. Seradjeh

This review paper comprehensively examines the influence of spatial torsion on quantum fluctuations from the perspectives of Metric-Affine Gravity (MAG) and the Stochastic Variational Method (SVM). We first outline the fundamental framework…

General Relativity and Quantum Cosmology · Physics 2026-03-19 Tomoi Koide , Armin van de Venn

We discuss Einstein-Klein-Gordon system in an environment of an infinite number of scalar fields leading to an external thermal noise. In the lowest order of metric and field perturbations the quadratic fluctuations consist of a sum of…

General Relativity and Quantum Cosmology · Physics 2019-05-22 Z. Haba

We study the geometric phase of a two-level atom coupled to an environment with Lorentzian spectral density. The non-Markovian effect on the geometric phase is explored analytically and numerically. In the weak coupling limit the…

Quantum Physics · Physics 2015-05-18 Juan-Juan Chen , Jun-Hong An , Qing-Jun Tong , Hong-Gang Luo , C. H. Oh

We study a mesoscopic ring with an in-line quantum dot threaded by an Aharonov-Bohm flux. Zero-point fluctuations of the electromagnetic environment capacitively coupled to the ring, with $\omega^s$ spectral density, can suppress tunneling…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Ning-Hua Tong , Matthias Vojta

Quantum errors in noisy environments remain a major obstacle to advancing quantum information technology. In this work, we expand a recently developed geometric framework, originally utilized for analyzing noise accumulation and creating…

Quantum Physics · Physics 2024-07-11 Junkai Zeng , Yong-Ju Hai , Hao Liang , Xiu-Hao Deng

The optically induced polarization of localized electron spins in an ensemble of quantum dots (QDs) dephases due to the interaction with the surrounding nuclear spins. Despite this dephasing, the spins in the QDs can be controlled to…

Mesoscale and Nanoscale Physics · Physics 2022-04-08 P. Schering , G. S. Uhrig

Electromagnetic modes are instrumental in building quantum machines. In this experiment, we introduce a method to manipulate these modes by effectively controlling their phase space. Preventing access to a single energy level, corresponding…

Coherent control of a spin is limited by both the decoherence due to coupling with the environment and noise coming from the quantized control. The quantum noise study of this system is particularly important in fault tolerant quantum…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Ching-Kit Chan , L. J. Sham

We study the phase space structure and the quantization of a pointlike particle in 2+1 dimensional gravity. By adding boundary terms to the first order Einstein Hilbert action, and removing all redundant gauge degrees of freedom, we arrive…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Hans-Juergen Matschull , Max Welling

Ballistic electrons flowing through a constriction can transfer momentum to the lattice and excite a vibration of a free-standing conductor. We show (both numerically and analytically) that the electromechanical noise power P does not…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. Tajic , M. Kindermann , C. W. J. Beenakker

Currents in a metallic ring with a quantum dot are studied in the framework of a Langevin equation for a magnetic flux passing through the ring. Two scenarios are considered: one in which thermal fluctuations of the dissipative part of the…

Mesoscale and Nanoscale Physics · Physics 2015-04-09 Lukasz Machura , Jerzy Łuczka

The dynamics of a quantum system with internal degrees of freedom undergoing spontaneous collapse in the position basis are analysed; e.g., neutral mesons or neutrinos. Surprisingly, the value of the Heaviside function $\theta(x)$ at $x=0$…

Quantum Physics · Physics 2016-02-18 K. Simonov , B. C. Hiesmayr

We experimentally investigate the effects of phase noise on the resonant and non-resonant dynamics of the atom-optics kicked rotor. Employing sinusoidal phase modulation at various frequencies, resonances are found corresponding to periodic…

Quantum Physics · Physics 2014-11-21 D. H. White , S. K. Ruddell , M. D. Hoogerland

Under ideal conditions, quantum metrology promises a precision gain over classical techniques scaling quadratically with the number of probe particles. At the same time, no-go results have shown that generic, uncorrelated noise limits the…

Quantum Physics · Physics 2017-07-13 J. B. Brask , R. Chaves , J. Kolodynski

Geometric phase phenomena in single neutrons have been observed in polarimeter and interferometer experiments. Interacting with static and time dependent magnetic fields, the state vectors acquire a geometric phase tied to the evolution…

Processing quantum information on continuous variables requires a highly nonlinear element in order to attain universality. Noise reduction in processing such quantum information involves the use of a nonlinear phase state as a non-Gaussian…

Quantum Physics · Physics 2019-11-27 Darren W. Moore , Andrey A. Rakhubovsky , Radim Filip

A large number of multifaceted quantum transport processes in molecular systems and physical nanosystems can be treated in terms of quantum relaxation processes which couple to one or several fluctuating environments. A thermal equilibrium…

Statistical Mechanics · Physics 2007-05-23 Igor Goychuk , Peter Hanggi

The classicalization of a decoherent discrete-time quantum walk on a line or an n-cycle can be demonstrated in various ways that do not necessarily provide a geometry-independent description. For example, the position probability…

Quantum Physics · Physics 2010-06-25 R. Srikanth , Subhashish Banerjee , C. M. Chandrashekar

A Langevin canonical framework for a chiral two-level system coupled to a bath of harmonic oscillators is used within a coupling scheme different from the well-known spin-boson model. From this stochastic dynamics, within the Markovian…