52,420 research outputs found
More on with a Root of Unity
Highest weight representations of with are
investigated. The structures of the irreducible hieghesat weight modules are
discussed in detail. The Clebsch-Gordan decomposition for the tensor product of
two irreducible representations is discussed. By using the results, a
representation of is also presented in terms of
holomorphic sections which also have index. Furthermore we realise
-graded supersymmetry in terms of the representation. An explicit
realization of via the heighest weight representation of
with is given.Comment: 24 page
Aging dynamics of ferromagnetic and reentrant spin glass phases in stage-2 CuCCl graphite intercalation compound
Aging dynamics of a reentrant ferromagnet stage-2
CuCoCl graphite intercalation compound has been studied
using DC magnetic susceptibility. This compound undergoes successive
transitions at the transition temperatures ( K) and
( K). The relaxation rate exhibits a
characteristic peak at below . The peak time as a
function of temperature shows a local maximum around 5.5 K, reflecting a
frustrated nature of the ferromagnetic phase. It drastically increases with
decreasing temperature below . The spin configuration imprinted at the
stop and wait process at a stop temperature () during the
field-cooled aging protocol, becomes frozen on further cooling. On reheating,
the memory of the aging at is retrieved as an anomaly of the
thermoremnant magnetization at . These results indicate the occurrence
of the aging phenomena in the ferromagnetic phase () as well
as in the reentrant spin glass phase ().Comment: 9 pages, 9 figures; submitted to Physical Review
Excited state TBA and functional relations in spinless Fermion model
The excited state thermodynamic Bethe ansatz (TBA) equations for the spinless
Fermion model are presented by the quantum transfer matrix (QTM) approach. We
introduce a more general family called T-functions and explore functional
relations among them (T-system) and their certain combinations (Y-system).
{}From their analytical property, we derive a closed set of non-linear integral
equations which characterize the correlation length of at
any finite temperatures. Solving these equations numerically, we explicitly
determine the correlation length, which coincides with earlier results with
high accuracy.Comment: 4 page
Orthonormalization procedure for chiral effective nuclear field theory
We show that the Q-box expansion of nuclear many-body physics can be applied
in nuclear effective field theory with explicit pions and external sources. We
establish the corresponding power counting and give an algorithm for the
construction of a hermitean and energy-independent potential for arbitrary
scattering processes on nucleons and nuclei to a given order in the chiral
expansion. Various examples are discussed in some detail.Comment: 22 pp, 12 fig
The light-cone gauge without prescriptions
Feynman integrals in the physical light-cone gauge are harder to solve than
their covariant counterparts. The difficulty is associated with the presence of
unphysical singularities due to the inherent residual gauge freedom in the
intermediate boson propagators constrained within this gauge choice. In order
to circumvent these non-physical singularities, the headlong approach has
always been to call for mathematical devices --- prescriptions --- some
successful ones and others not so much so. A more elegant approach is to
consider the propagator from its physical point of view, that is, an object
obeying basic principles such as causality. Once this fact is realized and
carefully taken into account, the crutch of prescriptions can be avoided
altogether. An alternative third approach, which for practical computations
could dispense with prescriptions as well as prescinding the necessity of
careful stepwise watching out of causality would be of great advantage. And
this third option is realizable within the context of negative dimensions, or
as it has been coined, negative dimensional integration method, NDIM for short.Comment: 9 pages, PTPTeX (included
Electronic Transport on the Shastry-Sutherland Lattice in Ising-type Rare Earth Tetraborides
In the presence of a magnetic field frustrated spin systems may exhibit
plateaus at fractional values of saturation magnetization. Such plateau states
are stabilized by classical and quantum mechanisms including order-by-disorder,
triplon crystallization, and various competing order effects. In the case of
electrically conducting systems, free electrons represent an incisive probe for
the plateau states. Here we study the electrical transport of Ising-type rare
earth tetraborides B (Er, Tm), a metallic Shastry-Sutherland lattice
showing magnetization plateaus. We find that the longitudinal and transverse
resistivities reflect scattering with both the static and dynamic plateau
structure. We model these results consistently with the expected strong
uniaxial anisotropy in a quantitative level, providing a framework for the
study of plateau states in metallic frustrated systems.Comment: 18 pages, 5 figure
Feynman integrals with tensorial structure in the negative dimensional integration scheme
Negative dimensional integration method (NDIM) is revealing itself as a very
useful technique for computing Feynman integrals, massless and/or massive,
covariant and non-covariant alike. Up to now, however, the illustrative
calculations done using such method are mostly covariant scalar integrals,
without numerator factors. Here we show how those integrals with tensorial
structures can also be handled with easiness and in a straightforward manner.
However, contrary to the absence of significant features in the usual approach,
here the NDIM also allows us to come across surprising unsuspected bonuses. In
this line, we present two alternative ways of working out the integrals and
illustrate them by taking the easiest Feynman integrals in this category that
emerges in the computation of a standard one-loop self-energy diagram. One of
the novel and as yet unsuspected bonus is that there are degeneracies in the
way one can express the final result for the referred Feynman integral.Comment: 9 pages, revtex, no figure
Negative dimensional approach for scalar two-loop three-point and three-loop two-point integrals
The well-known -dimensional Feynman integrals were shown, by Halliday and
Ricotta, to be capable of undergoing analytic continuation into the domain of
negative values for the dimension of space-time. Furthermore, this could be
identified with Grassmannian integration in positive dimensions. From this
possibility follows the concept of negative dimensional integration for loop
integrals in field theories. Using this technique, we evaluate three two-loop
three-point scalar integrals, with five and six massless propagators, with
specific external kinematic configurations (two legs on-shell), and four
three-loop two-point scalar integrals. These results are given for arbitrary
exponents of propagators and dimension, in Euclidean space, and the particular
cases compared to results published in the literature.Comment: 6 pages, 7 figures, Revte
Two-loop self-energy diagrams worked out with NDIM
In this work we calculate two two-loop massless Feynman integrals pertaining
to self-energy diagrams using NDIM (Negative Dimensional Integration Method).
We show that the answer we get is 36-fold degenerate. We then consider special
cases of exponents for propagators and the outcoming results compared with
known ones obtained via traditional methods.Comment: LaTeX, 10 pages, 2 figures, styles include
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