The dephasing rate formula in the many body context (2009)
Cohen, Doron, Von Delft, Jan, Marquardt, Florian, Imry, Yoseph
We suggest a straightforward approach to the calculation of the dephasing rate in a fermionic system, which correctly keeps track of the crucial physics of Pauli blocking. Starting from Fermi's...
Interaction-induced dynamical phase locking of Bose-Einstein condensates (2009)
Boukobza, Erez, Cohen, Doron, Vardi, Amichay
We show that interactions result in the emergence of a {\it definite} relative-phase between two initially incoherent Bose-Einstein condensates. The many-realization interference fringe visibility is...
Stotland, Alexander, Kottos, Tsampikos, Cohen, Doron
Semi-linear response theory determines the absorption coefficient of a driven system using a resistor network calculation: Each unperturbed energy level of a particle in a vibrating trap, or of an...
Purely electric spin pumping in one-dimension (2009)
Avishai, Yshai, Cohen, Doron, Nagaosa, Naoto
We show theoretically that a simple one dimensional system (such as metallic wire) can display quantum spin pumping possibly without pushing any charge. It is achieved by applying two slowly varying...
Quantum decay into a non-flat continuum (2009)
Aisenberg, James, Sela, Itamar, Kottos, Tsampikos, Cohen, Doron, Elgart, Alex
We study the decay of a prepared state into non-flat continuum. We find that the survival probability $P(t)$ might exhibit either stretched-exponential or power-law decay, depending on non-universal...
Occupation Statistics of a BEC for a Driven Landau-Zener Crossing (2009)
Smith-Mannschott, Katrina, Chuchem, Maya, Hiller, Moritz, Kottos, Tsampikos, Cohen, Doron
We consider an atomic Bose-Einstein condensate (BEC) loaded in a biased double-well trap with tunneling rate $K$ and inter-atomic interaction $U$. The BEC is prepared such that all $N$ atoms are in...
Phase-diffusion dynamics in weakly coupled Bose-Einstein condensates (2008)
Boukobza, Erez, Chuchem, Maya, Cohen, Doron, Vardi, Amichay
We study the phase-sensitivity of collisional phase-diffusion between weakly coupled Bose-Einstein condensates, using a semiclassical picture of the two-mode Bose-Hubbard model. When weak-coupling is...
Semilinear response for the heating rate of cold atoms in vibrating traps (2008)
Stotland, Alexander, Cohen, Doron, Davidson, Nir
The calculation of the heating rate of cold atoms in vibrating traps requires a theory that goes beyond the Kubo linear response formulation. If a strong "quantum chaos" assumption does not hold, the...
Quantum dynamics and transport in a double well system (2008)
The simplest one-dimensional model for the studying of non-trivial geometrical effects is a ring shaped device which is formed by joining two arms. We explore the possibility to model such a system...
Controlled quantum stirring of Bose-Einstein condensates (2008)
Hiller, Moritz, Kottos, Tsampikos, Cohen, Doron
By cyclic adiabatic change of two control parameters of an optical trap one can induce a circulating current of condensed bosons. The amount of particles that are transported per period depends on...
Quantum Stirring in low dimensional devices (2008)
A circulating current can be induced in the Fermi sea by displacing a scatterer, or more generally by integrating a quantum pump into a closed circuit. The induced current may have either the same or...
Renormalization of the dephasing by zero point fluctuations (2008)
Bandopadhyay, Swarnali, Cohen, Doron
We study the role of zero-point-fluctuations (ZPF) in dephasing at low temperature. Unlike the Caldeira-Leggett model where the interaction is with an homogeneous fluctuating field of force, here we...
Stotland, Alexander, Budoyo, Rangga, Peer, Tal, Kottos, Tsampikos, Cohen, Doron
The calculation of the conductance of disordered rings requires a theory that goes beyond the Kubo-Drude formulation. Assuming "mesoscopic" circumstances the analysis of the electro-driven...
Leveraging Web Services for Information Discovery (2007)
Doron Cohen, Michal Jacovi, Michael Herscovici, Yoelle S. Maarek, Noga Meshulam, Aya Soffer, ...
In this paper, we describe a novel application of the Web Services model for end-user information discovery needs rather than for the traditional business-to-business applications. We describe a...
Control of atomic currents using a quantum stirring device (2007)
Hiller, Moritz, Kottos, Tsampikos, Cohen, Doron
We propose a BEC stirring device which can be regarded as the incorporation of a quantum pump into a closed circuit: it produces a DC circulating current in response to a cyclic adiabatic change of...
Restricted quantum-classical correspondence and counting statistics for a coherent transition (2007)
The conventional probabilistic point of view implies that if a particle has a probability $p$ to make a transition from one site to another site, then the average transport should be $=p}$ with a...
Dephasing of a particle in a dissipative environment (2007)
Cohen, Doron, Horovitz, Baruch
The motion of a particle in a ring of length L is influenced by a dirty metal environment whose fluctuations are characterized by a short correlation distance $\ell > L$). A proper definition of the...
Decoherence of a particle in a ring (2007)
Cohen, Doron, Horovitz, Baruch
We consider a particle coupled to a dissipative environment and derive a perturbative formula for the dephasing rate based on the purity of the reduced probability matrix. We apply this formula to...
The amount $Q$ of particles that are transported via a path of motion is characterized by its expectation value $$ and by its variance $Var(Q)$. We analyze what happens if a particle has two optional...
EPR, Bell, Schrodinger's cat, and the Monty Hall Paradox (2007)
The purpose of this manuscript is to provide a short pedagogical explanation why "quantum collapse" is not a metaphysical event, by pointing out the analogy with a "classical collapse" which is...
From the Kubo formula to variable range hopping (2006)
Consider a multichannel closed ring with disorder. In the semiclassical treatment its conductance is given by the Drude formula. Quantum mechanics challenge this result both in the limit of strong...
The mesoscopic conductance of ballistic rings (2006)
Etzioni, Yoav, Bandopadhyay, Swarnali, Cohen, Doron
The calculation of the conductance of ballistic rings requires a theory that goes well beyond the Kubo-Drude formula. Assuming "mesoscopic" circumstance of very weak environmental relaxation, the...
Diffractive energy spreading and its semiclassical limit (2006)
Stotland, Alexander, Cohen, Doron
We consider driven systems where the driving induces jumps in energy space: (1) particles pulsed by a step potential; (2) particles in a box with a moving wall; (3) particles in a ring driven by an...
Lecture Notes in Quantum Mechanics (2006)
These lecture notes cover undergraduate textbook topics (e.g. as in Sakurai), and also additional advanced topics at the same level of presentation. In particular: EPR and Bell; Basic postulates; The...
The conductance of a multi-mode ballistic ring: beyond Landauer and Kubo (2006)
Bandopadhyay, Swarnali, Etzioni, Yoav, Cohen, Doron
The Landauer conductance of a two terminal device equals to the number of open modes in the weak scattering limit. What is the corresponding result if we close the system into a ring? Is it still...
Operating a quantum pump in a closed circuit (2005)
During an adiabatic pumping cycle a conventional two barrier quantum device takes an electron from the left lead and ejects it to the right lead. Hence the pumped charge per cycle is naively expected...
Wilkinson, Michael, Mehlig, Bernhard, Cohen, Doron
We discuss the response of a quantum system to a time-dependent perturbation with spectrum \Phi(\omega). This is characterised by a rate constant D describing the diffusion of occupation probability...
Quantum pumping and dissipation in closed systems (2005)
Current can be pumped through a closed system by changing parameters (or fields) in time. Linear response theory (the Kubo formula) allows to analyze both the charge transport and the associated...
Quantum stirring of particles in closed devices (2005)
Rosenberg, Gilad, Cohen, Doron
We study the quantum analog of stirring of water inside a cup using a spoon. This can be regarded as a prototype example for quantum pumping in closed devices. The current in the device is induced by...
Parametric invariant Random Matrix Model and the emergence of multifractality (2005)
Mendez-Bermudez, J. A., Kottos, Tsampikos, Cohen, Doron
We propose a random matrix modeling for the parametric evolution of eigenstates. The model is inspired by a large class of quantized chaotic systems. Its unique feature is having parametric...
Rate of energy absorption by a closed ballistic ring (2005)
Cohen, Doron, Kottos, Tsampikos, Schanz, Holger
We make a distinction between the spectroscopic and the mesoscopic conductance of closed systems. We show that the latter is not simply related to the Landauer conductance of the corresponding open...
The Multimode Conductance Formula for a Closed Ring (2005)
The multimode conductance of a {\em closed} ring is found within the framework of a scattering approach. The expression can be regarded as a generalization of the Landauer formula. The treatment is...
Mendez-Bermudez, J. A., Kottos, Tsampikos, Cohen, Doron
Considering a quantized chaotic system, we analyze the evolution of its eigenstates as a result of varying a control parameter. As the induced perturbation becomes larger, there is a crossover from a...
Quantum pumping: The charge transported due to a translation of a scatterer (2004)
Cohen, Doron, Kottos, Tsampikos, Schanz, Holger
The amount of charge which is pushed by a moving scatterer is $dQ = -G dX$, where $dX$ is the displacement of the scatterer. The question is what is $G$. Does it depend on the transmission $g_0$ of...
Driven chaotic mesoscopic systems, dissipation and decoherence (2004)
Driven chaotic systems are of interest in mesoscopic physics, as well as in nuclear, atomic and molecular physics. Such systems [coordinates $(Q,P)$]$ tend to absorb energy. This irreversible effect...
The information entropy of quantum mechanical states (2004)
Stotland, Alexander, Pomeransky, Andrei A., Bachmat, Eitan, Cohen, Doron
It is well known that a Shannon based definition of information entropy leads in the classical case to the Boltzmann entropy. It is tempting to regard the Von Neumann entropy as the corresponding...
Quantum Reversibility: Is there an Echo? (2003)
Hiller, Moritz, Kottos, Tsampikos, Cohen, Doron, Geisel, Theo
We study the possibility to undo the quantum mechanical evolution in a time reversal experiment. The naive expectation, as reflected in the common terminology ("Loschmidt echo"), is that maximum...
Quantum pumping in closed systems, adiabatic transport, and the Kubo formula (2003)
Quantum pumping in closed systems is considered. We explain that the Kubo formula contains all the physically relevant ingredients for the calculation of the pumped charge ($Q$) within the framework...
Quantum pumping and dissipation: from closed to open systems (2003)
Current can be pumped through a closed system by changing parameters (or fields) in time. The Kubo formula allows to distinguish between dissipative and non-dissipative contributions to the current....
Persistent currents in Möbius strips (2003)
Yakubo, Kousuke, Avishai, Yshai, Cohen, Doron, 矢久保, 考介
The relation between the geometry of a two-dimensional sample and its equilibrium physical properties is exemplified here for a system of noninteracting electrons on a Mo¨bius strip. Dispersion...
Persistent currents in Möbius strips (2003)
Yakubo, Kousuke, Avishai, Yshai, Cohen, Doron
The relation between the geometry of a two-dimensional sample and its equilibrium physical properties is
Persistent currents in Möbius strips (2003)
Yakubo, Kousuke, Avishai, Yshai, Cohen, Doron
The relation between the geometry of a two-dimensional sample and its equilibrium physical properties is
For chaotic systems there is a theory for the decay of the survival probability, and for the parametric dependence of the local density of states. This theory leads to the distinction between...
Quantum Dissipation due to the Interaction with Chaos (2003)
Cohen, Doron, Kottos, Tsampikos
We discuss the possibility of having "quantum dissipation" due to the interaction with chaotic degrees of freedom. We define the conditions that should be satisfied in order to have a dissipative...
Survival probability and local density of states for one-dimensional Hamiltonian systems (2003)
For chaotic systems there is a theory for the decay of the survival probability, and for the parametric dependence of the local density of states. This theory leads to the distinction between...
Two-Step Enantio-selective Optical Switch (2002)
Král, Petr, Thanopulos, Ioannis, Shapiro, Moshe, Cohen, Doron
We present an optical "enantio-selective switch", that, in two steps, turns a ("racemic") mixture of left-handed and right-handed chiral molecules into the enantiomerically pure state of interest....
Classical and quantum pumping in closed systems (2002)
Pumping of charge (Q) in a closed ring geometry is not quantized even in the strict adiabatic limit. The deviation form exact quantization can be related to the Thouless conductance. We use Kubo...
Non-perturbative response: chaos versus disorder (2002)
Cohen, Doron, Kottos, Tsampikos
Quantized chaotic systems are generically characterized by two energy scales: the mean level spacing $\Delta$, and the bandwidth $\Delta_b\propto\hbar$. This implies that with respect to driving such...
Stadium Billiard with Moving Walls (2002)
Cohen, Doron, Wisniacki, Diego A.
We study the evolution of the energy distribution for a stadium with moving walls. We consider one period driving cycle, which is characterized by an amplitude $A$ and wall velocity $V$. This...
Persistent currents in Moebius strips (2002)
Yakubo, Kousuke, Avishai, Yshai, Cohen, Doron
Relation between the geometry of a two-dimensional sample and its equilibrium physical properties is exemplified here for a system of non-interacting electrons on a Moebius strip. Dispersion relation...
Quantum Chaos, Irreversibility, dissipation and dephasing (2002)
The main idea of "Quantum Chaos" studies is that Quantum Mechanics introduces two energy scales into the study of chaotic systems: One is obviously the mean level spacing $\Delta\propto\hbar^d$,...
Quantum Irreversibility of Energy Spreading (2002)
Kottos, Tsampikos, Cohen, Doron
The analysis of dissipation and dephasing in driven mesoscopic devices requires a distinction between two notions of quantum irreversibility. One ("Loschmidt echo") is related to "time reversal",...
Personalized Pocket Directories for Mobile Devices (2002)
Cohen, Doron, Herscovici, Michael, Petruschka, Yael, Maarek, Yolle S., Soffer, Aya, Newbold, Dave
In spite of the increase in the availability of mobile devices in the last few years, Web information is not yet as accessible from PDAs or WAP phones as it is from the desktop. In this paper, we...
Wisniacki, Diego A., Cohen, Doron
The idea of perturbation independent decay (PID) has appeared in the context of survival-probability studies, and lately has emerged in the context of quantum irreversibility studies. In both cases...
Consolidating boundary methods for finding the eigenstates of billiards (2001)
Cohen, Doron, Lepore, Natasha, Heller, Eric J.
The plane-wave decomposition method (PWDM), a widely used means of numerically finding eigenstates of the Helmholtz equation in billiard systems is described as a variant of the mathematically...
Failure of random matrix theory to correctly describe quantum dynamics (2001)
Kottos, Tsampikos, Cohen, Doron
Consider a classically chaotic system which is described by a Hamiltonian H_0. At t=0 the Hamiltonian undergoes a sudden-change H_0 -> H. We consider the quantum-mechanical spreading of the evolving...
Dephasing due to the interaction with chaotic degrees of freedom (2001)
We consider the motion of a particle, taking into account its interaction with environmental degrees of freedom. The dephasing time is determined by the nature of the environment, and depends on the...
Static Index Pruning for Information Retrieval Systems (2001)
David Carmel, Doron Cohen, Ronald Fagin, Eitan Farchi, Michael Herscovici, Yoëlle S. Maarek, ...
We introduce static index pruning methods that significantly reduce the index size in information retrieval systems. We investigate uniform and term-based methods that each remove selected entries...
Static Index Pruning for Information Retrieval Systems (2001)
David Carmel, Doron Cohen, Ronald Fagin, Eitan Farchi, Michael Herscovici, ...
We introduce static index pruning methods that significantly reduce the index size in information retrieval systems. We investigate uniform and term-based methods that each remove selected entries...
Static Index Pruning for Information Retrieval Systems (2001)
David Carmel, Doron Cohen, Ronald Fagin, Eitan Farchi, Michael Herscovici, Yoëlle S. Maarek, ...
We introduce static indexp runingmeth ds thk significantly reduce th index size in information retrieval systems. We investigate uniform and term-basedmeth ds thk each remove selected entries fromth...
Overview: Brownian Motion and Dephasing due to Dynamical Disorder (2000)
The motion of a particle under the influence of a dynamical disorder is described by the DLD model. One motivation is to understand the motion of an electron inside a metal; Another is to understand...
Overview: Energy Absorption by Driven Mesoscopic Systems (2000)
There are three regimes in the theory of energy absorption: The adiabatic regime, the linear-response (Kubo) regime, and the non-perturbative regime. The mesoscopic Drude formula for electrical...
Parametric Evolution for a Deformed Cavity (2000)
Cohen, Doron, Barnett, Alex, Heller, Eric J.
We consider a classically chaotic system that is described by a Hamiltonian H(Q,P;x), where (Q,P) describes a particle moving inside a cavity, and x controls a deformation of the boundary. The...
Rate of energy absorption for a driven chaotic cavity (2000)
Barnett, Alex, Cohen, Doron, Heller, Eric J.
We consider the response of a chaotic cavity in d dimensions to periodic driving. We are motivated by older studies of one-body dissipation in nuclei, and also by anticipated mesoscopic applications....
Quantum-Mechanical Non-Perturbative Response of Driven Chaotic Mesoscopic Systems (2000)
Cohen, Doron, Kottos, Tsampikos
Consider a time-dependent Hamiltonian $H(Q,P;x(t))$ with periodic driving $x(t)=A\sin(\Omega t)$. It is assumed that the classical dynamics is chaotic, and that its power-spectrum extends over some...
Barnett, Alex, Cohen, Doron, Heller, Eric J.
We consider chaotic billiards in d dimensions, and study the matrix elements M_{nm} corresponding to general deformations of the boundary. We analyze the dependence of |M_{nm}|^2 on \omega =...
Cohen, Doron, Kottos, Tsampikos
We study a classically chaotic system which is described by a Hamiltonian $H(Q,P;x)$ where $(Q,P)$ are the canonical coordinates of a particle in a 2D well, and $x$ is a parameter. By changing $x$ we...
Collection Awareness on the Web via Livemaps (2000)
Doron Cohen, Michal Jacovi, Yoelle Maarek, Vladimir Soroka
With the increasing proliferation of chat applications on the Web, the old vision of “adding people ” to the Web, is becoming a reality. While infrastructure seems to be scalable and stable...
Chaos, Dissipation and Quantal Brownian Motion (1999)
Energy absorption by driven chaotic systems, the theory of energy spreading and quantal Brownian motion are considered. In particular we discuss the theory of a classical particle that interacts with...
We consider a classically chaotic system that is described by an Hamiltonian $H(Q,P;x)$ where x is a constant parameter. Our main interest is in the case of a gas-particle inside a cavity, where $x$...
Wavepacket dynamics in energy space, RMT and quantum-classical correspondence (1999)
Cohen, Doron, Izrailev, Felix M., Kottos, Tsampikos
We apply random-matrix-theory (RMT) to the analysis of evolution of wavepackets in energy space. We study the crossover from ballistic behavior to saturation, the possibility of having an...
Non Perturbative Destruction of Localization in the Quantum Kicked Particle Problem (1999)
The angle coordinate of the Quantum Kicked Rotator problem is treated as if it were an extended coordinate. A new mechanism for destruction of coherence by noise is analyzed using both heuristic and...
We make the first steps towards a generic theory for energy spreading and quantum dissipation. The Wall formula for the calculation of friction in nuclear physics and the Drude formula for the...
Chaos, Dissipation and Quantal Brownian Motion (1999)
ion in the theory of quantum dissipation and quantal Brownian motion. That question concerns the problem of quantal particle that interacts with quantal (chaotic) degrees of freedom. c fl Societ`a...
Chaos, Dissipation and Quantal Brownian Motion (1999)
ees of freedom. c fl Societ`a Italiana di Fisica 2 Doron Cohen 1. -- Definition of the problem We are interested in the reduced dynamics of a slow degree of freedom (x; p) that interacts with a bath....
Both in atomic physics and in mesoscopic physics it is sometimes interesting to consider the energy time-dependence of a parametrically-driven chaotic system. We assume an Hamiltonian ${\cal...
Dephasing at Low Temperatures (1998)
We discuss the significance and the calculation of dephasing at low temperatures. The particle is moving diffusively due to a static disorder configuration, while the interference between classical...
Quantal Brownian Motion - Dephasing and Dissipation (1998)
We analyze quantal Brownian motion in $d$ dimensions using the unified model for diffusion localization and dissipation, and Feynman-Vernon formalism. At high temperatures the propagator possess a...
Quantal-Classical Duality and the Semiclassical Trace Formula (1997)
Cohen, Doron, Primack, Harel, Smilansky, Uzy
We consider Hamiltonian systems which can be described both classically and quantum mechanically. Trace formulas establish links between the energy spectra of the quantum description and the spectrum...
Quantum Dissipation versus Classical Dissipation for Generalized Brownian Motion (1997)
We try to clarify what are the genuine quantal effects that are associated with generalized Brownian Motion (BM). All the quantal effects that are associated with the...
Periodic Orbits, Breaktime and Localization (1996)
The main goal of the present paper is to convince that it is feasible to construct a `periodic orbit theory' of localization by extending the idea of classical action correlations. This possibility...
Unified Model for The Study of Diffusion Localization and Dissipation (1996)
A new model that generalizes the study of quantum Brownian motion (BM) is constructed. We consider disordered environment that may be either static (quenched), noisy or dynamical. The...
Human fetal phonocardiography and the detection of fetal activity. (1989)
Thesis (Ph. D.)--University of Cambridge, 1989.