53531246
Lattice worldline representation of correlators in a background field
A bstractWe use a discrete worldline representation in order to study the continuum limit of the one-loop expectation value of dimension two and four local operators in a background field. We illustrate this technique in the case of a scalar field coupled to a non-Abelian background gauge field. The first two coefficients of the expansion in powers of the lattice spacing can be expressed as sums over random walks on a d-dimensional cubic lattice. Using combinatorial identities for the distribution of the areas of closed random walks on a lattice, these coefficients can be turned into simple integrals. Our results are valid for an anisotropic lattice, with arbitrary lattice spacings in each direction.
118497947
Properties of the Boltzmann equation in the classical approximation
We study the Boltzmann equation with elastic point-like scalar interac-tions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated col-lision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we con-sider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since one has also access to the non-approximated result for comparison.
119193432
On holographic thermalization and gravitational collapse of massless scalar fields
A bstractIn this paper we study thermalization in a strongly coupled system via AdS/CFT. Initially, the energy is injected into the system by turning on a spatially homogenous scalar source coupled to a marginal composite operator. The thermalization process is studied by numerically solving Einstein’s equations coupled to a massless scalar field in the Poincare patch of AdS5. We define a thermalization time tT on the AdS side, which has an interpretation in terms of a spacelike Wilson loop $ \left\langle {W\left( {l\tilde{-}\frac{1}{T}} \right)} \right\rangle $ in CFT. Here T is the thermal equilibrium temperature. We study both cases with the source turned on in short $ \left( {\varDelta t\lesssim \frac{1}{T}} \right) $ and long $ \left( {\varDelta t\gtrsim \frac{1}{T}} \right) $ durations. In the former case, the thermalization time $ {t_T}=\frac{gt }{T}\lesssim \frac{1}{T} $ and the coefficient $ {g_t}\tilde{-}0.73 $ in the limit $ \varDelta t\lesssim \frac{0.02 }{T} $. In the latter case, we find double- and multiple-collapse solutions, which may be interpreted as the gravity duals of two- or multi-stage thermalization in CFT. In all the cases our results indicate that such a strongly coupled system thermalizes in a typical time scale $ {t_T}\tilde{-}\frac{O(1) }{T} $.
118667819
On using cold baryogenesis to constrain the two-Higgs doublet model
A bstractWe consider the creation of the cosmological baryon asymmetry in the Two Higgs Doublet Model. We imagine a situation where the masses of the five Higgs particles and the two Higgs vevs are constrained by collider experiments, and demonstrate how the requirement of successful baryogenesis can be used to further constrain the remaining 4-dimensional parameter space of the model. We numerically compute the asymmetry within the scenario of Cold Electroweak Baryogenesis, which is particularly straightforward to simulate reliably.
119303364
Cold electroweak baryogenesis in the two Higgs-doublet model
A bstractWe perform the first investigation of cold electroweak baryogenesis in the two Higgs-doublet model (2HDM). The electroweak symmetry breaking transition is assumed to occur through a spinodal instability from a super-cooled initial state. We consider the creation of net Chern-Simons number, which through the axial anomaly is equivalent to a baryon asymmetry. CP violation is explicit in the scalar potential, but only in combination with P-violation is it possible for an asymmetry to be generated. This is introduced through the leading C-and P-breaking, but CP invariant, term expected to arise upon integrating out the fermions in the theory. We perform real-time lattice simulations of the transition, and find the coefficient of this term required for successful baryogenesis.
196069470
Reference Manual and User's Manual for ALICE DAQ Modelling and Simulation
59844874
Simulation of the ALICE DAQ System with GALSIM