125 research outputs found
(Quantumness in the context of) Resource Theories
We review the basic idea behind resource theories, where we quantify quantum
resources by specifying a restricted class of operations. This divides the
state space into various sets, including states which are free (because they
can be created under the class of operations), and those which are a resource
(because they cannot be). One can quantify the worth of the resource by the
relative entropy distance to the set of free states, and under certain
conditions, this is a unique measure which quantifies the rate of state to
state transitions. The framework includes entanglement, asymmetry and purity
theory. It also includes thermodynamics, which is a hybrid resource theory
combining purity theory and asymmetry. Another hybrid resource theory which
merges purity theory and entanglement can be used to study quantumness of
correlations and discord, and we present quantumness in this more general
framework of resource theories.Comment: review articl
Irreversibility for all bound entangled states
We derive a new inequality for entanglement for a mixed four-partite state.
Employing this inequality, we present a one-shot lower bound for entanglement
cost and prove that entanglement cost is strictly larger than zero for any
entangled state. We demonstrate that irreversibility occurs in the process of
formation for all non-distillable entangled states. In this way we solve a long
standing problem, of how "real" is entanglement of bound entangled states.
Using the new inequality we also prove impossibility of local-cloning of a
known entangled state.Comment: The publication version. As noted in quant-ph/0510035, the result
also implies that the mathematical definition of entangled states is
equivalent to the physical definition in the sense of states preparation by
LOC
Design and implementation of UHF patch antenna
This document contains the final report of designing and implementation of a patch antenna,among setting up of dimensions
(more information is included in chapter 5.1)
, comparing results from Momentum Microwave and real measurements, analyzing S11
parameters and others. At the beginning
it intends to explain what an antenna is. Then, types of antenna and characteristic of patch antenna will be presented. Next chapter is devoted to explain the
main parameters of antennas, for example radio patterns, directivity, gain, polarization, efficiency and even measurement techniques. This report
contains also tools and methods which have been used to design the specified
antenna. Also it describes Feature Selective Validation (FSV) for Validation of Computational Electromagnetic (CEM). Program that was used to designing process is Advance Design System shared by Universitat
Politècnica de Catalunya. Last chapter raises the main topic of this report, namely general information about designed antenna, simulation result, measurements, problems and final conclusion. At the end of
document bibliography is attached
Geometric picture of quantum discord for two-qubit quantum states
Among various definitions of quantum correlations, quantum discord has
attracted considerable attention. To find analytical expression of quantum
discord is an intractable task. Exact results are known only for very special
states, namely, two-qubit X-shaped states. We present in this paper a geometric
viewpoint, from which two-qubit quantum discord can be described clearly. The
known results about X state discord are restated in the directly perceivable
geometric language. As a consequence, the dynamics of classical correlations
and quantum discord for an X state in the presence of decoherence is endowed
with geometric interpretation. More importantly, we extend the geometric method
to the case of more general states, for which numerical as well as analytica
results about quantum discord have not been found yet. Based on the support of
numerical computations, some conjectures are proposed to help us establish
geometric picture. We find that the geometric picture for these states has
intimate relationship with that for X states. Thereby in some cases analytical
expressions of classical correlations and quantum discord can be obtained.Comment: 9 figure
A model for soap film dynamics with evolving thickness
Previous research on animations of soap bubbles, films, and foams largely focuses on the motion and geometric shape of the bubble surface. These works neglect the evolution of the bubble’s thickness, which is normally responsible for visual phenomena like surface vortices, Newton’s interference patterns, capillary waves, and deformation-dependent rupturing of films in a foam. In this paper, we model these natural phenomena by introducing the film thickness as a reduced degree of freedom in the Navier-Stokes equations and deriving their equations of motion. We discretize the equations on a nonmanifold triangle mesh surface and couple it to an existing bubble solver. In doing so, we also introduce an incompressible fluid solver for 2.5D films and a novel advection algorithm for convecting fields across non-manifold surface junctions. Our simulations enhance state-of-the-art bubble solvers with additional effects caused by convection, rippling, draining, and evaporation of the thin film
Classical information deficit and monotonicity on local operations
We investigate classical information deficit: a candidate for measure of
classical correlations emerging from thermodynamical approach initiated in
[Phys. Rev. Lett 89, 180402]. It is defined as a difference between amount of
information that can be concentrated by use of LOCC and the information
contained in subsystems. We show nonintuitive fact, that one way version of
this quantity can increase under local operation, hence it does not possess
property required for a good measure of classical correlations. Recently it was
shown by Igor Devetak, that regularised version of this quantity is monotonic
under LO. In this context, our result implies that regularization plays a role
of "monotoniser".Comment: 6 pages, revte
On asymptotic continuity of functions of quantum states
A useful kind of continuity of quantum states functions in asymptotic regime
is so-called asymptotic continuity. In this paper we provide general tools for
checking if a function possesses this property. First we prove equivalence of
asymptotic continuity with so-called it robustness under admixture. This allows
us to show that relative entropy distance from a convex set including maximally
mixed state is asymptotically continuous. Subsequently, we consider it arrowing
- a way of building a new function out of a given one. The procedure originates
from constructions of intrinsic information and entanglement of formation. We
show that arrowing preserves asymptotic continuity for a class of functions
(so-called subextensive ones). The result is illustrated by means of several
examples.Comment: Minor corrections, version submitted for publicatio
SEQUENCE STRATIGRAPHY OF THE NORTHERN DANUBE BASIN (SLOVAKIA)
Danube Basin Upper Miocene to Pliocene development is well recorded in its sedimentary succession, where three depositional sequences were documented (marked DB1, DB2 and DB3). First lacustrine depositional cycle (DB1) comprises the Lower to lowermost Upper Pannonian sediments (A–F zones sensu Papp 1951) represented by the Ivánka Formation and lower part of the Beladice Formation, deposited in time span 11.6–(9.7?) 8.9 Ma. Second lacustrine to alluvial depositional cycle (DB2) comprises the Upper Pannonian sediments (F, G and H zones sensu Papp 1951) represented by the upper part of the Beladice Formation and Volkovce Formation, deposited in time span 8.9 – 6.3? Ma. Third, alluvial depositional cycle (DB3) comprises the Danube Basin Upper Pliocene sediments represented by the Romanian Kolárovo Formation, dated 4.1? – 2.6 Ma
Local versus non-local information in quantum information theory: formalism and phenomena
In spite of many results in quantum information theory, the complex nature of
compound systems is far from being clear. In general the information is a
mixture of local, and non-local ("quantum") information. To make this point
more clear, we develop and investigate the quantum information processing
paradigm in which parties sharing a multipartite state distill local
information. The amount of information which is lost because the parties must
use a classical communication channel is the deficit. This scheme can be viewed
as complementary to the notion of distilling entanglement. After reviewing the
paradigm, we show that the upper bound for the deficit is given by the relative
entropy distance to so-called psuedo-classically correlated states; the lower
bound is the relative entropy of entanglement. This implies, in particular,
that any entangled state is informationally nonlocal i.e. has nonzero deficit.
We also apply the paradigm to defining the thermodynamical cost of erasing
entanglement. We show the cost is bounded from below by relative entropy of
entanglement. We demonstrate the existence of several other non-local
phenomena. For example,we prove the existence of a form of non-locality without
entanglement and with distinguishability. We analyze the deficit for several
classes of multipartite pure states and obtain that in contrast to the GHZ
state, the Aharonov state is extremely nonlocal (and in fact can be thought of
as quasi-nonlocalisable). We also show that there do not exist states, for
which the deficit is strictly equal to the whole informational content (bound
local information). We then discuss complementary features of information in
distributed quantum systems. Finally we discuss the physical and theoretical
meaning of the results and pose many open questions.Comment: 35 pages in two column, 4 figure
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