1,443 research outputs found
The vicinity of the phase transition in the lattice Weinberg - Salam Model
We investigated the lattice Weinberg - Salam model without fermions for the
Higgs mass around GeV. On the phase diagram there exists the vicinity of
the phase transition between the physical Higgs phase and the unphysical
symmetric phase, where the fluctuations of the scalar field become strong while
Nambu monopoles are dense. According to our numerical results (obtained on the
lattices of sizes up to ) the maximal value of the ultraviolet
cutoff in the model cannot exceed the value around TeV.Comment: Proceedings of QUARKS-201
Wigner transformation, momentum space topology, and anomalous transport
Using derivative expansion applied to the Wigner transform of the two - point
Green function we analyse the anomalous quantum Hall effect (AQHE), and the
chiral magnetic effect (CME). The corresponding currents are proportional to
the momentum space topological invariants. We reproduce the conventional
expression for the Hall conductivity in D. In D our analysis allows
to explain systematically the AQHE in topological insulators and Weyl
semimetals. At the same time using this method it may be proved, that the
equilibrium CME is absent in the wide class of solids, as well as in the
properly regularized relativistic quantum field theory.Comment: Latex, 26 page
How to approach continuum physics in lattice Weinberg - Salam model
We investigate lattice Weinberg - Salam model without fermions numerically
for the realistic choice of coupling constants correspondent to the value of
the Weinberg angle , and bare fine structure constant
around . We consider the values of the scalar self coupling
corresponding to Higgs mass GeV. It has been found
that nonperturbative effects become important while approaching continuum
physics within the lattice model. When the ultraviolet cutoff (where is the lattice spacing) is increased and achieves the
value around 1 TeV one encounters the fluctuational region (on the phase
diagram of the lattice model), where the fluctuations of the scalar field
become strong. The classical Nambu monopole can be considered as an embryo of
the unphysical symmetric phase within the physical phase. In the fluctuational
region quantum Nambu monopoles are dense and, therefore, the use of the
perturbation expansion around trivial vacuum in this region is limited. Further
increase of the cutoff is accompanied by a transition to the region of the
phase diagram, where the scalar field is not condensed (this happens at the
value of around 1.4 TeV for the considered lattice sizes). Within
this region further increase of the cutoff is possible although we do not
observe this in details due to the strong fluctuations of the gauge boson
correlator. Both mentioned above regions look unphysical. Therefore we come to
the conclusion that the maximal value of the cutoff admitted within lattice
Electroweak theory cannot exceed the value of the order of 1 TeV.Comment: 19 pages, 15 figures, to appear in Phys.Rev.
Analogies between the Black Hole Interior and the Type II Weyl Semimetals
In the Painleve--Gullstrand (PG) reference frame, the description of
elementary particles in the background of a black hole (BH) is similar to the
description of non-relativistic matter falling toward the BH center. The
velocity of the fall depends on the distance to the center, and it surpasses
the speed of light inside the horizon.~Another analogy to non-relativistic
physics appears in the description of the massless fermionic particle. Its
Hamiltonian inside the BH, when written in the PG reference frame, is identical
to the Hamiltonian of the electronic quasiparticles in type~II Weyl semimetals
(WSII) that reside in the vicinity of a type~II Weyl point. When these
materials are in the equilibrium state, the type II Weyl point becomes the
crossing point of the two pieces of the Fermi surface called Fermi pockets. {It
was previously stated} that there should be a Fermi surface inside a black hole
in equilibrium. In real materials, type II Weyl points come in pairs, and the
descriptions of the quasiparticles in their vicinities are, to a certain
extent, inverse. Namely, the directions of their velocities are opposite. In
line with the mentioned analogy, we propose the hypothesis that inside the
equilibrium BH there exist low-energy excitations moving toward the exterior of
the BH. These excitations are able to escape from the BH, unlike ordinary
matter that falls to its center. The important consequences to the quantum
theory of black holes follow.Comment: Latex, 7 page
Torsion instead of Technicolor
We consider the model, which contains a nonminimal coupling of Dirac spinors
to torsion. Due to the action for torsion that breaks parity the left - right
asymmetry of the spinors appears. This construction is used in order to provide
dynamical Electroweak symmetry breaking. Namely, we arrange all Standard Model
fermions in the left - handed spinors. The additional technifermions are
arranged in right - handed spinors. Due to interaction with torsion
technifermions are condensed and, therefore, cause appearance of gauge boson
masses. In order to provide all fermions with masses we consider two
possibilities. The first one is related to an additional coupling of a real
massive scalar field to considered spinors. The second possibility is to
introduce the mass term for the mentioned Dirac spinors composed of the
Standard Model fermions and the technifermions.Comment: LATEX, to appear in Mod.Phys.Lett.
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