52,670 research outputs found
Dimensional Deconstruction and Wess-Zumino-Witten Terms
A new technique is developed for the derivation of the Wess-Zumino-Witten
terms of gauged chiral lagrangians. We start in D=5 with a pure (mesonless)
Yang-Mills theory, which includes relevant gauge field Chern-Simons terms. The
theory is then compactified, and the effective D=4 lagrangian is derived using
lattice techniques, or ``deconstruction,'' where pseudoscalar mesons arise from
the lattice Wilson links. This yields the WZW term with the correct Witten
coefficient by way of a simple heuristic argument. We discover a novel WZW term
for singlet currents, that yields the full Goldstone-Wilczek current, and a
U(1) axial current for the skyrmion, with the appropriate anomaly structures. A
more detailed analysis is presented of the dimensional compactification of
Yang-Mills in D=5 into a gauged chiral lagrangian in D=4, heeding the
consistency of the D=4 and D=5 Bianchi identities. These dictate a novel
covariant derivative structure in the D=4 gauge theory, yielding a field
strength modified by the addition of commutators of chiral currents. The
Chern-Simons term of the pure D=5 Yang-Mills theory then devolves into the
correct form of the Wess-Zumino-Witten term with an index (the analogue of
N_{colors}=3) of N=D=5. The theory also has a Skyrme term with a fixed
coefficient.Comment: 29 pages, no figures; replacement fixes a typographical minus sign
error in eq.(16), an errant normalization factor, and clarifies some
discussion issue
Adaptive control of CO bending vibration: deciphering field-system dynamics
We combined adaptive closed-loop optimization, phase-shaping with a
restricted search space and imaging to control dynamics and decipher the
optimal pulse. The approach was applied to controlling the amplitude of CO
bending vibration during strong-field Coulomb explosion. The search space was
constrained by expressing the spectral phase as a Taylor series, which
generated pulses with characteristics commensurate with the natural physical
features of this problem. Optimal pulses were obtained that enhanced bending by
up to 56% relative to what is observed with comparably intense, transform
limited pulses. We show that (1) this judicious choice of a reduced parameter
set made unwrapping the dynamics more transparent and (2) the enhancement is
consistent with field-induced structural changes to a bent excited state of
CO, which theoretical simulations have identified as the state from
which the explosion originates.Comment: 4 pages, 3 figures, 1 table, added reference
The Complete Jamming Landscape of Confined Hard Discs
An exact description of the complete jamming landscape is developed for a
system of hard discs of diameter , confined between two lines separated
by a distance . By considering all possible local
packing arrangements, the generalized ensemble partition function of jammed
states is obtained using the transfer matrix method, which allows us to
calculate the configurational entropy and the equation of state for the
packings. Exploring the relationship between structural order and packing
density, we find that the geometric frustration between local packing
environments plays an important role in determining the density distribution of
jammed states and that structural "randomness" is a non-monotonic function of
packing density. Molecular dynamics simulations show that the properties of the
equilibrium liquid are closely related to those of the landscape.Comment: 5 Pages, 4 figure
Dynamics of axial separation in long rotating drums
We propose a continuum description for the axial separation of granular
materials in a long rotating drum. The model, operating with two local
variables, concentration difference and the dynamic angle of repose, describes
both initial transient traveling wave dynamics and long-term segregation of the
binary mixture. Segregation proceeds through ultra-slow logarithmic coarsening.Comment: 4 pages, 3 Postscript figures; submitted to PR
Energetics of Open Systems and Chemical Potential From Micro-Dynamics Viewpoints
We present the energetic aspect of open systems which may exchange particles
with their environments. Our attention shall be paid to the scale that the
motion of the particles is described by the classical Langevin dynamics. Along
a particular realization of the stochastic process, we study the energy
transfer into the open system from the environments. We are able to clarify how
much energy each particle carries when it enters or leaves the system. On the
other hand, the chemical potential should be considered as the concept in macro
scale, which is relevant to the free energy potential with respect to the
number of particles. Keywords: open systems, stochastic energetics, chemical
potentialComment: 7 pages, 1 figur
Validity of the second law in nonextensive quantum thermodynamics
The second law of thermodynamics in nonextensive statistical mechanics is
discussed in the quantum regime. Making use of the convexity property of the
generalized relative entropy associated with the Tsallis entropy indexed by q,
Clausius' inequality is shown to hold in the range of q between zero and two.
This restriction on the range of the entropic index, q, is purely quantum
mechanical and there exists no upper bound of q for validity of the second law
in classical theory.Comment: 12 pages, no figure
Topological Interactions in Warped Extra Dimensions
Topological interactions will be generated in theories with compact extra
dimensions where fermionic chiral zero modes have different localizations. This
is the case in many warped extra dimension models where the right-handed top
quark is typically localized away from the left-handed one. Using
deconstruction techniques, we study the topological interactions in these
models. These interactions appear as trilinear and quadrilinear gauge boson
couplings in low energy effective theories with three or more sites, as well as
in the continuum limit. We derive the form of these interactions for various
cases, including examples of Abelian, non-Abelian and product gauge groups of
phenomenological interest. The topological interactions provide a window into
the more fundamental aspects of these theories and could result in unique
signatures at the Large Hadron Collider, some of which we explore.Comment: 40 pages, 10 figures, 2 tables; modifications in the KK parity
discussion, final version at JHE
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