Einstein-Podolsky-Rosen correlations between two uniformly accelerated oscillators

We consider the quantum correlations, i.e. the entanglement, between two systems uniformly accelerated with identical acceleration a in opposite Rindler quadrants which have reached thermal equilibrium with the Unruh heat bath. To this end we study an exactly soluble model consisting of two oscillators coupled to a massless scalar field in 1+1 dimensions. We find that for some values of the parameters the oscillators get entangled shortly after the moment of closest approach. Because of boost invariance there are an infinite set of pairs of positions where the oscillators are entangled. The maximal entanglement between the oscillators is found to be approximately 1.4 entanglement bits.Comment: 11 page

Topological gravity on the lattice

In this paper we show that a particular twist of $\mathcal{N}=4$ super Yang-Mills in three dimensions with gauge group SU(2) possesses a set of classical vacua corresponding to the space of flat connections of the {\it complexified} gauge group $SL(2,C)$. The theory also contains a set of topological observables corresponding to Wilson loops wrapping non-trivial cycles of the base manifold. This moduli space and set of topological observables is shared with the Chern Simons formulation of three dimensional gravity and we hence conjecture that the Yang-Mills theory gives an equivalent description of the gravitational theory. Unlike the Chern Simons formulation the twisted Yang-Mills theory possesses a supersymmetric and gauge invariant lattice construction which then provides a possible non-perturbative definition of three dimensional gravity.Comment: 10 page

Engaging the ‘evil empire’ : East-West relations in the Second Cold War

Between 1980 and 1985, the rivalry between the United States and the Soviet Union underwent unexpected and profound change. US-Soviet relations transformed so rapidly that scholars have since used this as a textbook case of longstanding adversaries setting aside prior disagreements and beginning to cooperate. What explains these shifts? Why would the superpowers suddenly start to cooperate after an extended period of intense rivalry? Using archival evidence from both sides of the Iron Curtain, this dissertation locates the root causes of the end of the Cold War in the first half of the 1980s. Changing perceptions of the balance of power between East and West hastened the Cold War’s peaceful conclusion. In the capitals of the superpowers and non-superpowers alike, observers perceived the same fundamental trends. Upon taking office, Ronald Reagan and his advisors (and US allies) lamented the United States’ weak position, which discouraged overt diplomacy with the Kremlin. Over the next five years, the administration’s outlook brightened considerably, as the US economy recovered and that of the Soviet Union faltered. It was at this point that Washington began to engage the Kremlin in public, confident in renewed US and Western power. Eastern leaders took a similar view of the shift in the balance of power. Throughout the first half of the 1980s, Warsaw Pact leaders lamented the erosion of their position and looked for ways to arrest this decline. Given their growing concerns about long-term survival, they believed that they would have to engage with the West and accept less advantageous agreements than they might have pressed for even in the recent past. Using new, international evidence, this dissertation sheds fresh light on one of the most consequential historical events: the end of the Cold War. It also speaks to key debates in international relations, including the use of diplomacy as opposed to force, crisis stability, and alliance politics. In a world shaped by the end of the Cold War, a better understanding of that period will help policy-makers to better respond to today’s challenges.Histor

Transport through a quantum dot with SU(4) Kondo entanglement

We investigate a mesoscopic setup composed of a small electron droplet (dot) coupled to a larger quantum dot (grain) also subject to Coulomb blockade as well as two macroscopic leads used as source and drain. An exotic Kondo ground state other than the standard SU(2) Fermi liquid unambiguously emerges: an SU(4) Kondo correlated liquid. The transport properties through the small dot are analyzed for this regime, through boundary conformal field theory, and allow a clear distinction with other regimes such as a two-channel spin state or a two-channel orbital state.Comment: 13 pages, 3 figure

First results obtained using the CENBG nanobeam line: performances and applications

A high resolution focused beam line has been recently installed on the AIFIRA (“Applications Interdisciplinaires des Faisceaux d’Ions en Région Aquitaine”) facility at CENBG. This nanobeam line, based on a doublet–triplet configuration of Oxford Microbeam Ltd. OM-50™ quadrupoles, offers the opportunity to focus protons, deuterons and alpha particles in the MeV energy range to a sub-micrometer beam spot. The beam optics design has been studied in detail and optimized using detailed ray-tracing simulations and the full mechanical design of the beam line was reported in the Debrecen ICNMTA conference in 2008. During the last two years, the lenses have been carefully aligned and the target chamber has been fully equipped with particle and X-ray detectors, microscopes and precise positioning stages. The beam line is now operational and has been used for its firstapplications to ion beam analysis. Interestingly, this set-up turned out to be a very versatile tool for a wide range of applications. Indeed, even if it was not intended during the design phase, the ion optics configuration offers the opportunity to work either with a high current microbeam (using the triplet only) or with a lower current beam presenting a sub-micrometer resolution (using the doublet–triplet configuration). The performances of the CENBGnanobeam line are presented for both configurations. Quantitative data concerning the beam lateral resolutions at different beam currents are provided. Finally, the firstresults obtained for different types of application are shown, including nuclear reaction analysis at the micrometer scale and the firstresults on biological sample

Thermal quantum electrodynamics of nonrelativistic charged fluids

The theory relevant to the study of matter in equilibrium with the radiation field is thermal quantum electrodynamics (TQED). We present a formulation of the theory, suitable for non relativistic fluids, based on a joint functional integral representation of matter and field variables. In this formalism cluster expansion techniques of classical statistical mechanics become operative. They provide an alternative to the usual Feynman diagrammatics in many-body problems which is not perturbative with respect to the coupling constant. As an application we show that the effective Coulomb interaction between quantum charges is partially screened by thermalized photons at large distances. More precisely one observes an exact cancellation of the dipolar electric part of the interaction, so that the asymptotic particle density correlation is now determined by relativistic effects. It has still the $r^{-6}$ decay typical for quantum charges, but with an amplitude strongly reduced by a relativistic factor.Comment: 32 pages, 0 figures. 2nd versio