161,570 research outputs found
Notes on nonabelian (0,2) theories and dualities
In this paper we explore basic aspects of nonabelian (0,2) GLSM's in two
dimensions for unitary gauge groups, an arena that until recently has largely
been unexplored. We begin by discussing general aspects of (0,2) theories,
including checks of dynamical supersymmetry breaking, spectators and weak
coupling limits, and also build some toy models of (0,2) theories for bundles
on Grassmannians, which gives us an opportunity to relate physical anomalies
and trace conditions to mathematical properties. We apply these ideas to study
(0,2) theories on Pfaffians, applying recent perturbative constructions of
Pfaffians of Jockers et al. We discuss how existing dualities in (2,2)
nonabelian gauge theories have a simple mathematical understanding, and make
predictions for additional dualities in (2,2) and (0,2) gauge theories.
Finally, we outline how duality works in open strings in unitary gauge
theories, and also describe why, in general terms, we expect analogous
dualities in (0,2) theories to be comparatively rare.Comment: 93 pages, LaTeX; v2: typos fixe
Integrable representations of the quantum affine special linear superalgebra
The simple integrable modules with finite dimensional weight spaces are
classified for the quantum affine special linear superalgebra
\U_q(\hat{\mathfrak{sl}}(M|N)) at generic . Any such module is shown to be
a highest weight or lowest weight module with respect to one of the two natural
triangular decompositions of the quantum affine superalgebra depending on
whether the level of the module is zero or not. Furthermore, integrable
\U_q(\hat{\mathfrak{sl}}(M|N))-modules at nonzero levels exist only if or
is .Comment: 31 page
Prediction of narrow and resonances with hidden charm above 4 GeV
The interaction between various charmed mesons and charmed baryons are
studied within the framework of the coupled channel unitary approach with the
local hidden gauge formalism. Several meson-baryon dynamically generated narrow
and resonances with hidden charm are predicted with mass
above 4 GeV and width smaller than 100 MeV. The predicted new resonances
definitely cannot be accommodated by quark models with three constituent quarks
and can be looked for at the forthcoming PANDA/FAIR experiments.Comment: 4 pages, 3 figure
Cosmic rays in early star-forming galaxies and their effects on the interstellar medium
Galaxies at high redshifts with strong star formation are sources of
high-energy cosmic rays. These cosmic rays interact with the baryon and
radiation fields of the galactic environment via photo-pair, photo-pion and
proton-proton processes to produce charged and neutral pions, neutrons and
protons. The cosmic rays thereby deposit energy into the interstellar medium
(ISM) as they propagate. We show how energy transport and deposition by ultra
high-energy cosmic rays is regulated by the evolution of the galaxy, in
particular by the development of the galactic magnetic field. We show how the
particle-driven energy deposition can influence the thermal evolution of the
host and its surroundings. Using a parametric protogalaxy model, we calculate
the heating effect on the ISM as the cosmic rays are increasingly confined by
the magnetic evolution of the galaxy.Comment: 8 pages, 2 figures; Proceedings of the 35th International Cosmic Ray
Conference (ICRC2017), 10-20 July 2017, Bexco, Busan, Korea -
PoS(ICRC2017)28
Local dynamics in high-order harmonic generation using Bohmian trajectories
We investigate high-order harmonic generation from a Bohmian-mechanical
perspective, and find that the innermost part of the core, represented by a
single Bohmian trajectory, leads to the main contributions to the high-harmonic
spectra. Using time-frequency analysis, we associate this central Bohmian
trajectory to an ensemble of unbound classical trajectories leaving and
returning to the core, in agreement with the three step model. In the Bohmian
scenario, this physical picture builds up non-locally near the core via the
quantum mechanical phase of the wavefunction. This implies that the flow of the
wavefunction far from the core alters the central Bohmian trajectory. We also
show how this phase degrades in time for the peripheral Bohmian trajectories as
they leave the core region.Comment: 7 pages, 3 figures; the manuscript has been considerably extended and
modified with regard to the previous version
Direct diffusion through interpenetrating networks: Oxygen in titanium
How impurity atoms move through a crystal is a fundamental and recurrent
question in materials. The previous understanding of oxygen diffusion in
titanium relied on interstitial lattice sites that were recently found to be
unstable, making the diffusion pathways for oxygen unknown. Using
first-principles quantum-mechanical methods, we find three oxygen interstitial
sites in titanium, and quantify the multiple interpenetrating networks for
oxygen diffusion. Surprisingly, no single transition dominates, but all
contribute to diffusion.Comment: 10 pages, 3 figures; additional supporting materia
Atemporal diagrams for quantum circuits
A system of diagrams is introduced that allows the representation of various
elements of a quantum circuit, including measurements, in a form which makes no
reference to time (hence ``atemporal''). It can be used to relate quantum
dynamical properties to those of entangled states (map-state duality), and
suggests useful analogies, such as the inverse of an entangled ket. Diagrams
clarify the role of channel kets, transition operators, dynamical operators
(matrices), and Kraus rank for noisy quantum channels. Positive (semidefinite)
operators are represented by diagrams with a symmetry that aids in
understanding their connection with completely positive maps. The diagrams are
used to analyze standard teleportation and dense coding, and for a careful
study of unambiguous (conclusive) teleportation. A simple diagrammatic argument
shows that a Kraus rank of 3 is impossible for a one-qubit channel modeled
using a one-qubit environment in a mixed state.Comment: Minor changes in references. Latex 32 pages, 13 figures in text using
PSTrick
Competing orders and inter-layer tunnelling in cuprate superconductors: A finite temperature Landau theory
We propose a finite temperature Landau theory that describes competing orders
and interlayer tunneling in cuprate superconductors as an important extension
to a corresponding theory at zero temperature [Nature {\bf 428}, 53 (2004)],
where the superconducting transition temperature is defined in three
possible ways as a function of the zero temperature order parameter. For given
parameters, our theory determines without any ambiguity. In mono- and
double-layer systems we discuss the relation between zero temperature order
parameter and the associated transition temperature in the presence of
competing orders, and draw a connection to the puzzling experimental fact that
the pseudo-gap temperature is much higher than the corresponding energy scale
near optimum doping. Applying the theory to multi-layer systems, we calculate
the layer-number dependence of . In a reasonable parameter space the
result turns out to be in agreement with experiments.Comment: 5 pages, 3 figure
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