Sergei Khlebnikov

RESONANT DECAY OF COSMOLOGICAL BOSE CONDENSATES

We present results of fully nonlinear calculations of decay of the inflaton interacting with another scalar field X . Combining numerical results for a cosmologically interesting range of the resonance parameter, q{le}10{sup 6} , with analytical estimates, we extrapolate them to larger q . We find that scattering of X fluctuations off the Bose condensate is a very efficient mechanism limiting growth of X fluctuations. For a single-component X , the resulting variance, at large q , is much smaller than that obtained in the Hartree approximation. {copyright} {ital 1997} {ital The American Physical Society}

COSMIC STRINGS FROM PREHEATING

Abstract We investigate nonthermal phase transitions that may occur after post-inflationary preheating in a simple model of a two-component scalar field with the effective potential λ ( φ i 2 −v 2 ) 2 /4, where φ 1 is identified with the inflaton field. We use three-dimensional lattice simulations to investigate the full nonlinear dynamics of the model. Fluctuations of the fields generated during and after preheating temporarily make the effective potential convex in the φ 1 direction. The subsequent nonthermal phase transition with symmetry breaking leads to formation of cosmic strings even for v≫10 16 GeV. This mechanism of string formation, in a modulated (by the oscillating field φ 1 ) phase transition, is different from the usual Kibble mechanism.

FIRST-ORDER NONTHERMAL PHASE TRANSITION AFTER PREHEATING

During preheating after inflation, parametric resonance rapidly generates very large fluctuations of scalar fields. In models where the inflaton field

Shock waves in strongly coupled plasmas II

\phi

Quantum Phase Slips in the Presence of Finite-Range Disorder

oscillates in a double-well potential and interacts with another scalar field

Large metric perturbations from rescattering

X

Effect of Strain on Stripe Phases in the Quantum Hall Regime

, fluctuations of X can keep the \phi to -\phi symmetry temporarily restored. If the coupling of \phi to X is much stronger than the inflaton self-coupling, the subsequent symmetry breaking is a first-order phase transition. We demonstrate the existence of this nonthermal phase transition with lattice simulations of the full nonlinear dynamics of the interacting fields. In particular, we observe nucleation of an expanding bubble.

The geometry of the double gyroid wire network: quantum and classical

In a recent paper we have analyzed the AdS/CFT duals to shock waves propagating in the

Quasiparticle Scattering by Quantum Phase Slips in One-Dimensional Superfluids

\mathcal{N} = 4

Formation of Quantum Phase Slip Pairs in Superconducting Nanowires

plasma. Here we study further properties of the system. In the gravity description we consider the properties of the dual black holes, showing in particular that they are stationary black holes with expanding horizons. This is possible because the horizon is not compact; in the fluid, this corresponds to the situation when entropy is being produced and carried away to infinity. We also consider shocks in dimensionalities d other than four and find that, for plasmas whose duals are given by asymptotically AdS spaces, the exponential tail of the shock on the supersonic side shrinks as