1,721,294 research outputs found
Quantum correlations in a few-atom spin-1 Bose-Hubbard model
Full text linkWe study the thermal quantum correlations and entanglement in spin-1 Bose-Hubbard model with two and three particles. While we use negativity to calculate entanglement, more general non-classical correlations are quantified using a new measure based on a necessary and sufficient condition for zero-discord state. We demonstrate that the energy level crossings in the ground state of the system are signalled by both the behavior of thermal quantum correlations and entanglement
Holonomic quantum computation
No full textIn this brief review we describe the idea of holonomic quantum computation. The idea of geometric phase and holonomy is introduced in a general way and we provide few examples that should help the reader understand the issues involve
Berry's phase in cavity QED: Proposal for observing an effect of field quantization
Full text linkA feasible experiment was proposed to investigate quantum effects in geometric phases, arising when a classical source drives not a single quantum system, but two interacting ones. The study shows how to observe a signature of the quantization of the electromagnetic field through a vacuum effect in Berry's phase. The interaction of an atom and a quantized cavity mode altogether driven by an external quasiclassical field is described
Coherent quantum evolution via reservoir driven holonomies.
Full text linkWe show that in the limit of a strongly interacting environment a system initially prepared in a decoherence-free subspace (DFS) coherently evolves in time, adiabatically following the changes of the DFS. If the reservoir cyclicly evolves in time, the DFS states acquire a holonomy
Distributions and channel capacities in generalized statistical mechanics
No full textThe purpose of this note is twofold. Firstly, we consider generalizations of Shannon's entropy and its application to thermodynamics based on extensivity considerations. Secondly, we apply the generalized entropy formalism to deriving various generalized channel capacities. We arrive at some surprising conclusions of systems achieving "super-capacitance" or "sub-capacitance" depending on the circumstances. These results suggest the possibility of improving the conventional Shannon capacity by using physical systems obeying more generalized statistics, but also predict behaviour which is hard to reconcile with experience
Anyons and transmutation of statistics via a vacuum-induced Berry phase
No full textA method to simulate the dynamics of anyons through the Jaynes-Cummings model is presented. The simulation of anyons with m/2, m/3, m/4 statistics and transmution of statistics of the system from Fermi to Bose, through the anyonics statistics was also shown. The entanglement of the system eigenstates which provides a two-dimensional confinement in the effective evolution of the system plays an important role. It is also shown that it is possible to transmute the statistics of the system continuall7 from ferminons to bosons for particular parameters
Quantumness and entanglement witnesses
No full textWe analyze the recently introduced notion of quantumness witnesses and compare it to that of entanglement witnesses. We show that any entanglement witness is also a quantumness witness. We then consider some physically relevant examples and explicitly construct some witnesses. © 2012 IOP Publishing Ltd
Engineering statistical transmutation of identical quantum particles
Full text linkA fundamental pillar of quantum mechanics concerns indistinguishable quantum particles. In three dimensions they may be classified into fermions or bosons, having, respectively, antisymmetric or symmetric wave functions under particle exchange. One of the numerous manifestations of this quantum statistics is the tendency of fermions (bosons) to antibunch (bunch). In a two-particle scattering experiment with two possible outgoing channels [C. K. Hong, Z. Y. Ou, and L. Mandel, Phys. Rev. Lett. 59, 2044 (1987)], the probability of the two particles to arrive each at a different terminal is enhanced (with respect to classical particles) for fermions, and reduced for bosons. Here we show that by entangling the particles with an external degree of freedom, we can engineer quantum statistical transmutation, which may cause fermions to bunch. Our analysis may have consequences on the observed fractional statistics of anyons, including non-Abelian statistics, with serious implications for quantum computing operations in the presence of external degrees of freedom
Non-adiabatic Vacuum induced Berry phase
No full textWe investigate quantum effects in geometric phases arising when a two-level system is interacting with a quantized electromagnetic field
Geometric phase in open systems.
No full textWe calculate the geometric phase associated with the evolution of a system subjected to decoherence through a quantum-jump approach. The method is general and can be applied to many different physical systems. As examples, two main sources of decoherence are considered: dephasing and spontaneous decay. We show that the geometric phase is completely insensitive to the former, i.e., it is independent of the number of jumps determined by the dephasing operator
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