3,911 research outputs found
Supertraces on the algebra of observables of the rational Calogero model based on the classical root system
A complete set of supertraces on the algebras of observables of the rational
Calogero models with harmonic interaction based on the classical root systems
of B_N, C_N and D_N types is found. These results extend the results known for
the case A_N. It is shown that there exist Q independent supertraces where
Q(B_N)=Q(C_N) is a number of partitions of N into a sum of positive integers
and Q(D_N) is a number of partitions of N into a sum of positive integers with
even number of even integers.Comment: 10 pages, LATE
The BLG Theory in Light-Cone Superspace
The light-cone superspace version of the d=3, N=8 superconformal theory of
Bagger, Lambert and Gustavsson (BLG) is obtained as a solution to constraints
imposed by OSp(2,2|8) superalgebra. The Hamiltonian of the theory is shown to
be a quadratic form of the dynamical supersymmetry transformation.Comment: 45 pages, v2: reference added, minor typos corrected, published
versio
Poisson-Lie T-duality and N=2 superconformal WZNW models on compact groups
The supersymmetric generalization of Pisson-Lie T-duality in N=2
superconformal WZNW models on the compact groups is considered. It is shown
that the role of Drinfeld's doubles play the complexifications of the
corresponding compact groups. These complex doubles are used to define the
natural actions of the isotropic subgroups forming the doubles on the group
manifolds of the N=2 superconformal WZNW models. The Poisson- Lie T-duality in
N=2 superconformal U(2)-WZNW model considered in details. It is shown that this
model admits Poisson-Lie symmetries with respect to the isotropic subgroups
forming Drinfeld's double Gl(2,C). Poisson-Lie T-duality transformation maps
this model into itself but acts nontrivialy on the space of classical
solutions. Supersymmetric generalization of Poisson-Lie T-duality in N=2
superconformal WZNW models on the compact groups of higher dimensions is
proposed.Comment: 12 pages, latex, misprints correcte
Exotic fermion multiplets as a solution to baryon asymmetry, dark matter and neutrino masses
We propose an extension to the standard model where three exotic fermion
5-plets and one scalar 6-plet are added to the particle content. By demanding
that all interactions are renormalizable and standard model gauge invariant, we
show that the lightest exotic particle in this model can be a dark matter
candidate as long as the new 6-plet scalar does not develop a nonzero vacuum
expectation value. Furthermore, light neutrino masses are generated radiatively
at one-loop while the baryon asymmetry is produced by the CP-violating decays
of the second lightest exotic particle. We have demonstrated using concrete
examples that there is a parameter space where a consistent solution to the
problems of baryon asymmetry, dark matter and neutrino masses can be obtained.Comment: 17 pages, 2 figures (REVTeX4.1), v2: some refs added, v3: typos
corrected, Sec.VI.B, C modified, this version to appear in PR
Zeta-Function Regularization is Uniquely Defined and Well
Hawking's zeta function regularization procedure is shown to be rigorously
and uniquely defined, thus putting and end to the spreading lore about
different difficulties associated with it. Basic misconceptions,
misunderstandings and errors which keep appearing in important scientific
journals when dealing with this beautiful regularization method ---and other
analytical procedures--- are clarified and corrected.Comment: 7 pages, LaTeX fil
Orbital order-disorder transition in La(1-x)Nd(x)MnO(3) (x = 0.0-1.0) and La(1-x-y)Nd(yx)Sr(y)MnO(3) (x = 0.1; y = 0.05,0.1)
The nature of orbital order-disorder transition has been studied in the
La(1-x)Nd(x)MnO(3) (x = 0.0-1.0) series which covers the entire range between
two end points - LaMnO(3) and NdMnO(3) - as well as in
La(0.85)Nd(0.1)Sr(0.05)MnO(3) and La(0.8)Nd(0.1)Sr(0.1)MnO(3). It has been
observed that the first-order nature of the transition gives way to higher
order with the increase in "x" in the case of pure manganites. The latent heat
(L) associated with the transition, first, drops with a steeper slope within x
= 0.0-0.3 and, then, gradually over a range 0.3<x<0.9. This drop could,
possibly, be due to evolution of finer orbital domain structure with "x". In
the case of Sr-doped samples, the transition appears to be of higher-order
nature even for a doping level 5 at%. In both cases, of course, the transition
temperature T(JT) rises systematically with the drop in average A-site radius
or rise in average Mn-O-Mn bond bending angle while no
apparent correlation could be observed with doping induced disorder sigma^2.
The cooperative nature of the orbital order, therefore, appears to be robust.Comment: 15 pages including 4 figures; pdf onl
Saturation field of frustrated chain cuprates: broad regions of predominant interchain coupling
An efficient and precise thermodynamic method to extract the interchain
coupling (IC) of spatially anisotropic 2D or 3D spin-1/2 systems from their
empirical saturation field H_s (T=0) is proposed. Using density-matrix
renormalization group, hard-core boson, and spin-wave theory we study how H_s
is affected by an antiferromagnetic (AFM) IC between frustrated chains
described in the J_1-J_2-spin model with ferromagnetic 1st and AFM 2nd neighbor
in-chain exchange. A complex 3D-phase diagram has been found. For Li2CuO2 and
Y2Ca2Cu5O10, we show that H_s is solely determined by the IC and predict H_s
approx 61 T for the latter.Using H_s approx 55 T from our high-field pulsed
measurements one reads out a weak IC for Li2CuO2 close to that from neutron
scattering.Comment: 4 pages, 6 figures, slightly revised version including a slightly
changed title and abstract, one new figure and an EPAPS-supplementatary part
have been adde
Pure spinor superfields -- an overview
Maximally supersymmetric theories do not allow off-shell superspace
formulations with traditional superfields containing a finite set of auxiliary
fields. It has become clear that off-shell supersymmetric action formulations
of such models can be achieved by the introduction of pure spinors. In this
talk, an overview of this formalism is given, with emphasis on D=10
super-Yang-Mills theory and D=11 supergravity. This a somewhat expanded version
of a talk presented at the workshop "Breaking of supersymmetry and ultraviolet
divergences in extended supergravity" (BUDS), Laboratori Nazionali di Frascati,
March 25-28, 2013.Comment: 34 pp., 2 figs., contributions to the proceedings of the workshop
"Breaking of supersymmetry and ultraviolet divergences in extended
supergravity" (BUDS), Laboratori Nazionali di Frascati, March 25-28, 201
On dilaton dependence of type II superstring action
The supersymmetric action of type IIA D=10 superstring in N=2a, D=10
supergravity background can be derived by double dimensional reduction of the
action of supermembrane coupled to D=11 supergravity. We demonstrate that the
background Ramond-Ramond fields appear in the resulting superstring action with
an extra factor of exponential of the dilaton.Comment: 6 pages, harvmac (references added
Reentrant metallic transition at a temperature above Tc at the breakdown of cooperative Jahn-Teller orbital order in perovskite manganites
We report an interesting reentrant metallic resistivity pattern beyond a
characteristic temperature T* which is higher than other such characteristic
transition temperatures like T(c)(Curie point), T(N) (Neel point), T(CO)
(charge order onset point) or T(OO) (orbital order onset point) in a range of
rare-erath perovskite manganites (RE(1-x)A(x)MnO(3); RE = La, Nd, Y; A = Sr,
Ca; x = 0.0-0.5). Such a behavior is normally observed in doped manganites with
doping level (x) higher than the critical doping level x(c) (= 0.17-0.22)
required for the metallic ground state to emerge and hence in a system where
cooperative Jahn-Teller orbital order has already undergone a breakdown.
However, the observation made in the La(1-x)Ca(x)MnO(3) (x = 0.0-0.5) series
turns out to be an exception to this general trend.Comment: 15 pages including 3 figures; pdf onl
- …