Non-supersymmetric Microstates of the MSW System

We present an analysis parallel to that of Giusto, Ross, and Saxena (arXiv:0708.3845) and construct a discrete family of non-supersymmetric microstate geometries of the Maldacena-Strominger-Witten system. The supergravity configuration in which we look for the smooth microstates is constructed using SO(4,4) dualities applied to an appropriate seed solution. The SO(4,4) approach offers certain technical advantages. Our microstate solutions are smooth in five dimensions, as opposed to all previously known non-supersymmetric microstates with AdS3 cores, which are smooth only in six dimensions. The decoupled geometries for our microstates are related to global AdS3 x S2 by spectral flows.Comment: 38 pages, including appendices and references; v2 refs + one paragraph adde

Entanglement of multiparty stabilizer, symmetric, and antisymmetric states

We study various distance-like entanglement measures of multipartite states under certain symmetries. Using group averaging techniques we provide conditions under which the relative entropy of entanglement, the geometric measure of entanglement and the logarithmic robustness are equivalent. We consider important classes of multiparty states, and in particular show that these measures are equivalent for all stabilizer states, symmetric basis and antisymmetric basis states. We rigorously prove a conjecture that the closest product state of permutation symmetric states can always be chosen to be permutation symmetric. This allows us to calculate the explicit values of various entanglement measures for symmetric and antisymmetric basis states, observing that antisymmetric states are generally more entangled. We use these results to obtain a variety of interesting ensembles of quantum states for which the optimal LOCC discrimination probability may be explicitly determined and achieved. We also discuss applications to the construction of optimal entanglement witnesses

Spin chains and channels with memory

In most studies of the channel capacity of quantum channels, it is assumed that the errors in each use of the channel are independent. However, recent work has begun to investigate the effects of memory or correlations in the error. This work has led to speculation that interesting non-analytic behaviour may occur in the capacity. Motivated by these observations, we connect the study of channel capacities under correlated error to the study of critical behaviour in many-body physics. This connection enables us the techniques of many-body physics to either completely solve or understand qualitatively a number of interesting models of correlated error. The models can display analogous behaviour to associated many-body systems, including `phase transitions'.Comment: V2: changes in presentation, some additional comments on generalisation. V3: In accordance with published version, most (but not all) details of proofs now included. A separate paper will shortly be submitted separately with all details and more result

Bounds on Multipartite Entangled Orthogonal State Discrimination Using Local Operations and Classical Communication

We show that entanglement guarantees difficulty in the discrimination of orthogonal multipartite states locally. The number of pure states that can be discriminated by local operations and classical communication is bounded by the total dimension over the average entanglement. A similar, general condition is also shown for pure and mixed states. These results offer a rare operational interpretation for three abstractly defined distance like measures of multipartite entanglement.Comment: 4 pages, 1 figure. Title changed in accordance with jounral request. Major changes to the paper. Intro rewritten to make motivation clear, and proofs rewritten to be clearer. Picture added for clarit

Entangled states maximize the two qubit channel capacity for some Pauli channels with memory

We prove that a general upper bound on the maximal mutual information of quantum channels is saturated in the case of Pauli channels with an arbitrary degree of memory. For a subset of such channels we explicitly identify the optimal signal states. We show analytically that for such a class of channels entangled states are indeed optimal above a given memory threshold. It is noteworthy that the resulting channel capacity is a non-differentiable function of the memory parameter.Comment: 4 pages no figure

Topology and Phases in Fermionic Systems

There can exist topological obstructions to continuously deforming a gapped Hamiltonian for free fermions into a trivial form without closing the gap. These topological obstructions are closely related to obstructions to the existence of exponentially localized Wannier functions. We show that by taking two copies of a gapped, free fermionic system with complex conjugate Hamiltonians, it is always possible to overcome these obstructions. This allows us to write the ground state in matrix product form using Grassman-valued bond variables, and show insensitivity of the ground state density matrix to boundary conditions.Comment: 4 pages, see also arxiv:0710.329

Quantum Entanglement of Electromagnetic Fields in Non-inertial Reference Frames

Recently relativistic quantum information has received considerable attention due to its theoretical importance and practical application. Especially, quantum entanglement in non-inertial reference frames has been studied for scalar and Dirac fields. As a further step along this line, we here shall investigate quantum entanglement of electromagnetic fields in non-inertial reference frames. In particular, the entanglement of photon helicity entangled state is extensively analyzed. Interestingly, the resultant logarithmic negativity and mutual information remain the same as those for inertial reference frames, which is completely different from that previously obtained for the particle number entangled state.Comment: more explanatory material added in the introduction, version to appear in Journal of Physics

TCT-442 Comparison of contemporary DES of different stent geometry and Absorb in a Swine Carotid – Jugular Thrombogenicity Shunt Model

The ECOPEL cruise series were part of the "Estudo do Ecossistema Pelágico do Extremo Sul do Brasil" project conducted by the Department of Oceanography of the Federal University of Rio Grande. The four seasonal cruises covered a region between the 32ºS and 34º30'S in the South Brazil Shelf. Ten transects (11 on the 1st cruise) perpendicular to the coastline with stations spaced 20 nautical miles (~ 37 km) apart were performed by the research vessel Atlantico Sul, and resulted in approximately 57 oceanographic stations per cruise limited to the 500 m isobath (Vasconcellos & Castello, 1996; Marcon, 2003). Ichthyoplankton samples were obtained by oblique trawls with a 0.6 m mouth diameter 300 ?m mesh size bongo net coupled with a flowmeter. Speed tows were approximately 1.3 m s -1 (2.5 kt). The trawls were performed between the surface and 5 m above the bottom in shallow water, and from 200 m depth to the surface in the deep stations. The samples were fixed and preserved in formaldehyde solution, buffered with sodium tetraborate, diluted in sea water with a final approximate concentration of 4%. The volume filtered was calculated and used to standardize the abundance of fish eggs and larvae per 100 m3 of filtered water (Vasconcellos et al., 1998; Marcon, 2003)