37,760 research outputs found
phi-fourth model on a circle
The four dimensional critical scalar theory at equilibrium with a thermal
bath at temperature is considered. The thermal equilibrium state is labeled
by the winding number of the vacua around the compact imaginary-time
direction which compactification radius is 1/T. The effective action for zero
modes is a three dimensional scalar theory in which the mass of the
the scalar field is proportional to resembling the Kaluza-Klein
dimensional reduction. Similar results are obtained for the theory at zero
temperature but in a one-dimensional potential well. Since parity is violated
by the vacua with odd vacuum number , in such cases there is also a cubic
term in the effective potential. The -term contribution to the vacuum
shift at one-loop is of the same order of the contribution from the
-term in terms of the coupling constant of the four dimensional theory
but becomes negligible as tends to infinity. Finally, the relation between
the scalar classical vacua and the corresponding SU(2) instantons on
in the 't Hooft ansatz is studied.Comment: 9 pages, revtex4, to appear in Phys.Lett.
Pseudogap, charge order, and pairing density wave at the hot spots in cuprate superconductors
We address the timely issue of the presence of charge ordering at the
hot-spots in the pseudo-gap phase of cuprate superconductors in the context of
an emergent SU(2)-symmetry which relates the charge and pairing sectors.
Performing the Hubbard-Stratonovich decoupling such that the free energy stays
always real and physically meaningful we exhibit three solutions of the
spin-fermion model at the hot spots. A careful examination of their stability
and free energy shows that, at low temperature, the system tends towards a
co-existence of charge density wave (CDW) and the composite order parameter
made of diagonal quadrupolar density wave and pairing fluctuations of Ref.
[Nat. Phys. , 1745 (2013)].The CDW is sensitive to the shape of the
Fermi surface in contrast to the diagonal quadrupolar order, which is immune to
it. SU(2) symmetry within the pseudo-gap phase also applies to the CDW state,
which therefore admits a pairing density pave counterpart breaking time
reversal symmetry.Comment: 15 pages, 15 figures, final version + typo corrected in Eq. (12
Detection of Exotic Massive Hadrons in Ultra High Energy Cosmic Ray Telescopes
We investigate the detection of exotic massive strongly interacting hadrons
(uhecrons) in ultra high energy cosmic ray telescopes. The conclusion is that
experiments such as the Pierre Auger Observatory have the potential to detect
these particles. It is shown that uhecron showers have clear distinctive
features when compared to proton and nuclear showers. The simulation of uhecron
air showers, and its detection and reconstruction by fluorescence telescopes is
described. We determine basic cuts in observables that will separate uhecrons
from the cosmic ray bulk, assuming this is composed by protons. If these are
composed by heavier nucleus the separation will be much improved. We also
discuss photon induced showers. The complementarity between uhecron detection
in accelerator experiments is discussed.Comment: 9 page 9 figure
Charge orders, magnetism and pairings in the cuprate superconductors
We review the recent developments in the field of cuprate superconductors
with the special focus on the recently observed charge order in the underdoped
compounds. We introduce new theoretical developments following the study of the
antiferromagnetic (AF) quantum critical point (QCP) in two dimensions, in which
preemptive orders in the charge and superconducting (SC) sectors emerged, that
are in turn related by an SU(2) symmetry. We consider the implications of this
proliferation of orders in the underdoped region, and provide a study of the
type of fluctuations which characterize the SU(2) symmetry. We identify an
intermediate energy scale where the SU(2) pairing fluctuations are dominant and
argue that they are unstable towards the formation of a Resonant Peierls
Excitonic (RPE) state at the pseudogap (PG) temperature . We discuss the
implications of this scenario for a few key experiments.Comment: 16 pages, 17 figure
Hopf Structures on Ambiskew Polynomial Rings
We derive necessary and sufficient conditions for an ambiskew polynomial ring
to have a Hopf algebra structure of a certain type. This construction
generalizes many known Hopf algebras, for example U(sl2), U_q(sl2) and the
enveloping algebra of the 3-dimensional Heisenberg Lie algebra. In a
torsion-free case we describe the finite-dimensional simple modules, in
particular their dimensions and prove a Clebsch-Gordan decomposition theorem
for the tensor product of two simple modules. We construct a Casimir type
operator and prove that any finite-dimensional weight module is semisimple.Comment: 23 page
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