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We study the measurement process by treating classical detectors entirely quantum mechanically. As a generic model we use a point-contact detector coupled to an electron in a quantum dot and tunneling into the continuum. Transition to the…

Quantum Physics · Physics 2007-05-23 S. A. Gurvitz

We study the dynamics of a charge qubit, consisting of a single electron in a double well potential, coupled to a point-contact (PC) electrometer using the quantum trajectories formalism. In contrast with previous work, our analysis is…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 T. M. Stace , S. D. Barrett

Entanglement often increases quantum measurement schemes' sensitivity. However, we find that in precision measurements with zero-mean Gaussian states, such as squeezed states, entanglement between different paths degrades measurement…

Quantum Physics · Physics 2025-04-28 Benjamin Lou , Hudson A. Loughlin , Nergis Mavalvala

Despite compelling evidence to the contrary in recent years, the view still persists that quantum effects cannot survive very long within a warm, noisy and complex environment that washes out quantum effects at timescales far too short for…

Quantum Physics · Physics 2014-07-09 A. D. Godbeer , J. S. Al-Khalili , P. D. Stevenson

The interplay between information-scrambling Hamiltonians and local continuous measurements hosts platforms for exotic measurement-induced phase transition in out-of-equilibrium steady states. Here, we consider such transitions under the…

Quantum Physics · Physics 2024-07-17 Chun Y. Leung , Alessandro Romito

Three different manifestations of the quantum Zeno effect are discussed, compared and shown to be physically equivalent. We look at frequent projective measurements, frequent unitary "kicks" and strong continuous coupling. In all these…

Quantum Physics · Physics 2010-01-31 P. Facchi , S. Pascazio

In this paper we give a new way to quantify the folklore notion that quantum measurements bring a disturbance to the system being measured. We consider two observers who initially assign identical mixed-state density operators to a…

Quantum Physics · Physics 2009-11-06 Christopher A. Fuchs , Kurt Jacobs

The ability to isolate a quantum system from its environment is of fundamental interest and importance in optical quantum science and technology. Here we propose an experimentally feasible scheme for beating environment-induced dissipation…

Quantum Physics · Physics 2024-07-15 Yi-Ming Xia , Yi-Fei Wang , Xiao-Yun Zhang , Hai-Chao Li , Wei Xiong

Monitored quantum systems evolve along stochastic trajectories correlated with the observer's knowledge of the system's state. Under such dynamics, certain quantum resources like entanglement may depend on the observer's state of knowledge.…

Quantum Physics · Physics 2024-09-04 Christian Carisch , Oded Zilberberg , Alessandro Romito

The quantum Zeno effect is a distinctive phenomenon in quantum mechanics, describing the nontrivial effect of frequent projective measurements on hindering the evolution of a quantum system. However, when subjected to environmental noise,…

Quantum Physics · Physics 2024-12-05 Haorui Chen , Shengshi Pang

We discuss the effect of semitransparency in a quantum-Zeno-like interaction-free measurement setup, a quantum-physics based approach that might significantly reduce sample damage in imaging and microscopy. With an emphasis on applications…

Quantum Physics · Physics 2014-12-03 Sebastian Thomas , Christoph Kohstall , Pieter Kruit , Peter Hommelhoff

The dynamics of any quantum system is unavoidably influenced by the external environment. Thus, the observation of a quantum system (probe) can allow the measure of the environmental features. Here, to spectrally resolve a noise field…

Quantum Physics · Physics 2020-03-27 Matthias M. Müller , Stefano Gherardini , Nicola Dalla Pozza , Filippo Caruso

We consider the dynamics of a system coupled to a thermal bath, going beyond the standard two-level system through the addition of an energy excitation degree of freedom. Further extensions are to systems containing many fermions, with the…

Quantum Physics · Physics 2011-08-04 Nicole F. Bell , R. F. Sawyer , Raymond R. Volkas

Repeated observations of a quantum system interacting with another one can drive the latter toward a particular quantum state, irrespectively of its initial condition, because of an {\em effective non-unitary evolution}. If the target state…

Quantum Physics · Physics 2018-07-24 B. Militello , K. Yuasa , H. Nakazato , A. Messina

We propose an approach to measuring nonresonant coupled systems, which gives a parametrically smaller error than the conventional fast projective measurements. The approach takes into account that, due to the coupling, excitations are not…

Quantum Physics · Physics 2009-03-05 L. Fedichkin , M. Shapiro , M. I. Dykman

The effect of a number of mechanisms designed to suppress decoherence in open quantum systems are studied with respect to their effectiveness at slowing down the loss of entanglement. The effect of photonic band-gap materials and frequency…

Quantum Physics · Physics 2013-07-09 Sandeep K Goyal , Subhashish Banerjee , Sibasish Ghosh

As a realization of the quantum Zeno effect, we consider electron tunneling between two quantum dots with one of the dots coupled to a quantum point contact detector. The coupling leads to decoherence and to the suppression of tunneling.…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 G. Hackenbroich , B. Rosenow , H. A. Weidenmueller

It is generally impossible to probe a quantum system without disturbing it. However, it is possible to exploit the back-action of quantum measurements and strong couplings to tailor and protect the coherent evolution of a quantum system.…

We review and discuss the potential of using measurement-based elements in quantum communication schemes, where certain tasks are realized with the help of entangled resource states that are processed by measurements. We consider long-range…

Quantum Physics · Physics 2016-09-27 M. Zwerger , H. J. Briegel , W. Dür

An iterative random procedure is considered allowing an entanglement purification of a class of multi-mode quantum states. In certain cases, a complete purification may be achieved using only a single signal state preparation. A physical…

Quantum Physics · Physics 2009-11-10 J Clausen , L Knoell , D-G Welsch