The Experts below are selected from a list of 153003 Experts worldwide ranked by ideXlab platform
Lev Vaidman - One of the best experts on this subject based on the ideXlab platform.
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Tracing the past of a Quantum Particle
Physical Review A, 2014Co-Authors: Lev VaidmanAbstract:The question ``Where was a Quantum Particle between pre- and postselection measurements?'' is analyzed in view of a recent proposal that the Quantum Particle was in the overlap of the forward and backward evolving wave functions. It is argued that this proposal corresponds not only to the criterion of where the Particle leaves a weak trace but also to the criterion of where the local interactions can affect the probability of postselection and where finding the Particle in a strong nondemolition measurement is possible. The concept of a ``secondary presence'' of a pre- and postselected Particle where local interactions affect the weak trace in the overlap region is introduced.
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Past of a Quantum Particle
Physical Review A, 2013Co-Authors: Lev VaidmanAbstract:Although there is no consensus regarding the ``reality'' of the past of a Quantum Particle, in situations where there is only one trajectory with a nonvanishing Quantum wave of the Particle between its emission and detection points, it seems ``safe'' to associate the past of the Particle with this trajectory. A method for analyzing the past of a Quantum Particle according to the weak trace it leaves is proposed. Such a trace can be observed via measurements performed on an ensemble of identically pre- and postselected Particles. Examples in which this method contradicts the above common sense description of the past of the Particle are presented. It is argued that it is possible to describe the past of a Quantum Particle, but the naive approach has to be replaced by both forward- and backward-evolving Quantum states.
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Where Is the Quantum Particle between Two Position Measurements
International Conference on Quantum Information, 2008Co-Authors: Lev VaidmanAbstract:A controversy about counterfactual computation reveals a paradoxical feature of a pre- and post-selected Quantum Particle: it can reach a certain location without being on the path that leads to and from this location.
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Measurement of an integral of a classical field with a single Quantum Particle
Physical Review A, 2005Co-Authors: Lev Vaidman, Amir KalevAbstract:A method for measuring an integral of a classical field via local interaction of a single Quantum Particle in a superposition of 2{sup N} states is presented. The method is as efficient as a Quantum method with N qubits passing through the field one at a time and it is exponentially better than any known classical method that uses N bits passing through the field one at a time. A related method for searching a string with a Quantum Particle is proposed.
Li Ming - One of the best experts on this subject based on the ideXlab platform.
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Design of Classifier Based on Weighted Quantum Particle Swarm
Computer Engineering, 2010Co-Authors: Li MingAbstract:Aiming at the shortage of Support Vector Machine(SVM) slow practice speed in the case of large sample,this paper introduces weighted optimal position strategy to improve Quantum Particle Swarm Optimization(QPSO) algorithm,processes coding for voice parameters by improving Michigan coding scheme,and constructs new classified rule fitness function to realize designing of classifier based on weighted Quantum Particle swarm.Application results of speaker recognition show that this classifier has better performance of noise proof and recognition speed.
Amir Kalev - One of the best experts on this subject based on the ideXlab platform.
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Measurement of an integral of a classical field with a single Quantum Particle
Physical Review A, 2005Co-Authors: Lev Vaidman, Amir KalevAbstract:A method for measuring an integral of a classical field via local interaction of a single Quantum Particle in a superposition of 2{sup N} states is presented. The method is as efficient as a Quantum method with N qubits passing through the field one at a time and it is exponentially better than any known classical method that uses N bits passing through the field one at a time. A related method for searching a string with a Quantum Particle is proposed.
Borivoje Dakic - One of the best experts on this subject based on the ideXlab platform.
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two way communication with a single Quantum Particle
Physical Review Letters, 2018Co-Authors: Flavio Del Santo, Borivoje DakicAbstract:In this Letter we show that communication when restricted to a single information carrier (i.e., single Particle) and finite speed of propagation is fundamentally limited for classical systems. On the other hand, Quantum systems can surpass this limitation. We show that communication bounded to the exchange of a single Quantum Particle (in superposition of different spatial locations) can result in "two-way signaling," which is impossible in classical physics. We quantify the discrepancy between classical and Quantum scenarios by the probability of winning a game played by distant players. We generalize our result to an arbitrary number of parties and we show that the probability of success is asymptotically decreasing to zero as the number of parties grows, for all classical strategies. In contrast, Quantum strategy allows players to win the game with certainty.
Rodolfo Figari - One of the best experts on this subject based on the ideXlab platform.
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A Model of a Quantum Particle in a Quantum Environment: A Numerical Study
Communications in Computational Physics, 2015Co-Authors: Raffaele Carlone, Rodolfo Figari, Claudia NegulescuAbstract:We define and investigate, via numerical analysis, a one dimensional toy- model of a cloud chamber. An energetic Quantum Particle, whose initial state is a su- perposition of two identical wave packets with opposite average momentum, interacts during its evolution and exchanges (small amounts of) energy with an array of local- ized spins. Triggered by the interaction with the environment, the initial superposition state turns into an incoherent sum of two states describing the following situation: or the Particle is going to the left and a largenumber of spins on the left side changed their states, or the same is happening on the right side. This evolution is reminiscent of what happens in a cloud chamber where a Quantum Particle, emitted as a spherical wave by a radioactive source, marks its passage inside a supersaturated vapour-chamber in the form of a sequence of small liquid bubbles arranging themselves around a possible classical trajectory of the Particle.
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Classical-Like Trajectories of a Quantum Particle in a Cloud Chamber
Lecture Notes in Physics, 2015Co-Authors: Gianfausto Dell’antonio, Rodolfo Figari, Alessandro TetaAbstract:We review old and new explanations of a case of Quantum Particle evolution with an intriguing phenomenology: the formation of Particle tracks in a tracking chamber. We recall the early debate on the subject at the fifth Solvay Conference and we present the out of the mainstream point of view assumed by Mott to examine the problem in 1929. We then give some details on recent results clarifying and making rigorous as well as generalizing Mott’s analysis. In the conclusions, we propose some new directions of research and some open problems in the topic.
