Elasticity and melting of skyrmion flux lattices in p-wave superconductors

We analytically calculate the energy, magnetization curves [B(H)], and elasticity of Skyrmions flux lattices in p-wave superconductors near the lower critical field H(c1), and we use these results with the Lindemann criterion to predict their melting curve. In striking contrast to vortex flux lattices, which always melt at an external field H>H(c1), Skyrmion flux lattices never melt near H(c1). This provides a simple and unambiguous test for the presence of Skyrmions.     

Dynamics of 2D anisotropic solids,smectics and nematics

In this research we study the critical dynamics of anisotropic layers in the various transition and crossover regimes associated with a defect unbinding picture of the melting process. We derive dynamic equations of motion for anisotropic solids, smectics and nematics, in the presence of defects and predict the critical behavior of various transport coefficients. The theory is applicable to two-dimensional layers of freely suspended liquid crystals, on which dynamic light-scattering experiments can be performed to test the predictions of the theory.     

Bell inequalities with auxiliary communication

What is the communication cost of simulating the correlations produced by quantum theory? We generalize Bell inequalities to the setting of local realistic theories augmented by a fixed amount of classical communication. Suppose two parties choose one of M two-outcome measurements and exchange 1 bit of information. We present the complete set of inequalities for M=2, and the complete set of inequalities for the joint correlation observable for M=3. We find that correlations produced by quantum theory satisfy both of these sets of inequalities. One bit of communication is therefore sufficient to simulate quantum correlations in both of these scenarios.     

A Generalized Grothendieck Inequality and Nonlocal Correlations that Require High Entanglement

Suppose that Alice and Bob make local two-outcome measurements on a shared entangled quantum state. We show that, for all positive integers d, there exist correlations that can only be reproduced if the local Hilbert-space dimension is at least d. This establishes that the amount of entanglement required to maximally violate a Bell inequality must depend on the number of measurement settings, not just the number of measurement outcomes. We prove this result by establishing a lower bound on a new generalization of Grothendieck’s constant.     

The picosecond transient Raman spectra of S1 excited oligophenyls, oxazols and stilbene derivatives

Picosecond time-resolved resonance Raman spectra of electronically excited laser-dye molecules, oligophenyls, oxazols, and stilbene derivatives in solution have been obtained. The spectral profiles of several transients are observed to change on the picosecond timescale.     

A new upper limit for the branching ratio for the decay η → π0e+e−

We have looked for the decay η → π⁰e⁺e^? in an optical spark chamber experiment at the Rutherford Laboratory. Our observations are consistent with no events being seen and give an upper limit rate (η → π⁰e⁺e^?)/ rate (η → all) < 4.5 × 10^?5 (90% C.L.).     

A measurement of the electromagnetic form factor of the eta meson and of the branching ratio for the eta Dalitz decay

In an optical spark chamber experiment we have obtained a sample of 80 eta Dalitz decays (η → e⁺e^?γ) and have measured the eta electromagnetic form factor to be F(X) = 1.0?(0.22 ±0.45)X, where X=M_ee²/M_η², and the branching ratio (η→e⁺e^?γ/(η→π⁺π^?π⁰)= (0.0082 ± 0.0020).