1,645 research outputs found
M-theory on pp-waves with a holomorphic superpotential and its membrane and matrix descriptions
We study a new class of inhomogeneous pp-wave solutions with 8 unbroken
supersymmetries in D=11 supergravity. The 9 dimensional transverse space is
Euclidean and split into 3 and 6 dimensional subspaces. The solutions have
non-constant gauge flux, which are described in terms of an arbitrary
holomorphic function of the complexified 6 dimensional space. The supermembrane
and matrix theory descriptions are also provided and we identify the relevant
supersymmetry transformation rules. The action also arises through a
dimensional reduction of N=1, D=4 supersymmetric Yang-Mills theory coupled to 3
gauge adjoint and chiral multiplets, whose interactions are determined by the
holomorphic function of the supergravity solution now constituting the
superpotential.Comment: 19 pages;v2 21p, added discussion and ref
Classification of the BPS states in Bagger-Lambert Theory
We classify, in a group theoretical manner, the BPS configurations in the
multiple M2-brane theory recently proposed by Bagger and Lambert. We present
three types of BPS equations preserving various fractions of supersymmetries:
in the first type we have constant fields and the interactions are purely
algebraic in nature; in the second type the equations are invariant under
spatial rotation SO(2), and the fields can be time-dependent; in the third
class the equations are invariant under boost SO(1,1) and provide the
eleven-dimensional generalizations of the Nahm equations. The BPS equations for
different number of supersymmetries exhibit the division algebra structures:
octonion, quarternion or complex.Comment: 28+1 pages, No figure; v2 Sec.3.3 slightly expanded, typos fixed; v3
some comments added, to appear in JHE
The Solar-Type Contact Binary BX Pegasi Revisited
We present the results of new CCD photometry for the contact binary BX Peg,
made during three successive months beginning on September 2008. As do
historical light curves, our observations display an O'Connell effect and the
November data by themselves indicate clear evidence for very short-time
brightness disturbance. For these variations, model spots are applied
separately to the two data set of Group I (Sep.--Oct.) and Group II (Nov.). The
former is described by a single cool spot on the secondary photosphere and the
latter by a two-spot model with a cool spot on the cool star and a hot one on
either star. These are generalized manifestations of the magnetic activity of
the binary system. Twenty light-curve timings calculated from Wilson-Devinney
code were used for a period study, together with all other minimum epochs. The
complex period changes of BX Peg can be sorted into a secular period decrease
caused dominantly by angular momentum loss due to magnetic stellar wind
braking, a light-travel-time (LTT) effect due to the orbit of a low-mass third
companion, and a previously unknown short-term oscillation. This last period
modulation could be produced either by a second LTT orbit with a period of
about 16 yr due to the existence of a fourth body or by the effect of magnetic
activity with a cycle length of about 12 yr.Comment: 23 pages, including 6 figures and 8 tables, accepted for publication
in PAS
Distinguishable Cash, Bosonic Bitcoin, and Fermionic Non-fungible Token
Modern technology has brought novel types of wealth. In contrast to hard
cashes, digital currencies do not have a physical form. They exist in
electronic forms only. Yet, it has not been clear what impacts their ongoing
growth will make, if any, on wealth distribution. Here we propose to identify
all forms of contemporary wealth into two classes: 'distinguishable' or
'identical'. Traditional tangible moneys are all distinguishable. Financial
assets and cryptocurrencies, such as bank deposits and Bitcoin, are boson-like,
while non-fungible tokens are fermion-like. We derive their ownership-based
distributions in a unified manner. Each class follows essentially the Poisson
or the geometric distribution. We contrast their distinct features such as Gini
coefficients. Further, aggregating different kinds of wealth corresponds to a
weighted convolution where the number of banks matters and Bitcoin follows
Bose-Einstein distribution. Our proposal opens a new avenue to understand the
deepened inequality in modern economy, which is based on the statistical
physics property of wealth rather than the individual ability of owners. We
call for verifications with real data.Comment: 8 pages including 3 figures; v2) Eqns (46) and (47) added, minor
changes, version to appear in Frontiers in Physic
Physical Properties of the Transiting Planetary System TrES-3
We present four new transits of the planetary system TrES-3 observed between
2009 May and 2010 June. Among these, the third transit by itself indicates
possible evidence for brightness disturbance, which might be the result of the
planet blocking a cool starspot on the stellar surface. A total of 109 transit
times, including our measurements, were used to determine the improved
ephemeris with a transit epoch of 2454185.9109440.000072 HJED and an
orbital period of 1.306187000.00000015 d. We analyzed the transit light
curves using the JKTEBOP code and adopting the quadratic limb-darkening law. In
order to derive the physical properties of the TrES-3 system, the transit
parameters are combined with the empirical relations from eclipsing binary
stars and stellar evolutionary models. The stellar mass and radius obtained
from a calibration using , log and [Fe/H] are consistent
with those from the isochrone analysis. We found that the exoplanet TrES-3b has
a mass of 1.930.07 M, a radius of 1.300.04 R,
a surface gravity of log =3.450.02, a density of 0.820.06
, and an equilibrium temperature of 164123 K. The results
are in good agreement with theoretical models for gas giant planets.Comment: 15 pages, including 4 figures and 4 tables, accepted for publication
in PAS
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