20,497 research outputs found
Orbital physics of polar Fermi molecules
We study a system of polar dipolar fermions in a two-dimensional optical
lattice and show that multi-band Fermi-Hubbard model is necessary to discuss
such system. By taking into account both on-site, and long-range interactions
between different bands, as well as occupation-dependent inter- and intra-band
tunneling, we predict appearance of novel phases in the strongly-interacting
limit
Non-equilibrium phonon dynamics in trapped ion systems
We propose a concrete experiment to probe the non-equilibrium local dynamics
of the one-dimensional Bose-Hubbard model using a trapped ion system consisting
of a linear chain of few Ba^+ ions prepared in a state of transverse motional
mode which corresponds to a fixed number of phonons per ion. These phonons are
well-known to be described by an effective Bose-Hubbard model. We propose a
protocol which leads to a sudden local sign reversal of the on-site interaction
strength of this Hubbard model at one of the sites and demonstrate that the
subsequent non-equilibrium dynamics of the model can be experimentally probed
by measuring the time-dependent phonon number in a specific motional state of
the Ba+ ions. We back our experimental proposal with exact numerical
calculation of the dynamics of a Bose-Hubbard model subsequent to a local
quench.Comment: The submission contains 5 pages and 4 figure
Bertrand competition with intertemporal demand
In the text-book model of dynamic Bertrand competition,
competing firms meet the same demand function every period. This is not a
satisfactory model of the demand side if consumers can make intertemporal
substitution between periods. Each period then leaves some residual demand
to future periods, and consumers who observe price under-cutting may correctly
anticipate an ensuing price war and therefore postpone their purchases.
Accordingly, the interaction between the firms no longer constitutes a repeated
game, and hence falls outside the domain of the usual Folk theorems.
We analyze collusive pricing in such situations, and study cases when consumers
have perfect and imperfect foresight and varying degrees of patience.
It turns out that collusion against patient and forward-looking consumers is
easier to sustain than collusion in the text-book model
Existence of Nearest Neighbor and Variable Range Hopping in PrZnMnO
A joint investigation of X-ray diffraction (XRD) pattern and Raman spectrum
authenticate the double phase monoclinic P21/n and cubic Fd-3m structures of
polycrystalline Pr2ZnMnO6 (PZM). The existence of two different conduction
mechanisms (Nearest neighbor hopping and Motts variable range hopping) is
observed using a combined study of conductivity, dielectric relaxation and
impedance spectra in PZM. This investigation point towards a transition from
nearest neighbor hoping to Motts variable range hopping mechanism due to
lowering activation energy around 580 K. The charge carriers hopping between
the localized acceptor states at the grain boundaries (GBs), which dominants
conduction mechanism below 580 K. The ac conductivity, dielectric relaxation,
Nyquist plot, and electric modulus highlight the blended effect of grains (Gs)
and GBs leads to the charge carrier dynamics in PZM. The dielectric relaxation
and modulus formalism are analyzed on the basis of empirical Cole-Cole model.
The conduction mechanism is found to be highly correlated with the relaxation
mechanism and impedance spectroscopy.Comment: 15 page
Minimal SUGRA Model and Collider Signals
The SUSY signals in the dominant stau-neutralino coannihilation region at a
500(800) GeV linear collider are investigated. The region is consistent with
the WMAP measurement of the cold dark matter relic density as well as all other
current experimental bounds within the mSUGRA framework. The signals are
characterized by an existence of very low-energy tau leptons in the final state
due to small mass difference between stau_1 and chi_1 (5-15 GeV). We study the
accuracy of the mass difference measurement with a 1^deg active mask to reduce
a huge SM two-photon background.Comment: 4 pages, 3 figures, Talk presented at ICHEP04, Aug.16-22, Beijing,
China, Numerical typos in Table 5 and 6 are corrected, no changes in figures
and in other numerical result
- âŚ