3,790 research outputs found
Spin Versus Charge Density Wave Order in Graphene-like Systems
A variational technique is used to study sublattice symmetry breaking by
strong on-site and nearest neighbor interactions in graphene. When interactions
are strong enough to break sublattice symmetry, and with relative strengths
characteristic of graphene, a charge density wave Mott insulator is favored
over the spin density wave condensates. In the spin density wave condensate we
find that introduction of a staggered on-site energy (quasiparticle mass) leads
to a splitting of the fermi velocities and mass gaps of the quasiparticle spin
states.Comment: 5 pages, 4 figures; some comments adde
Maximally entangled fermions
Fermions play an essential role in many areas of quantum physics and it is
desirable to understand the nature of entanglement within systems that consists
of fermions. Whereas the issue of separability for bipartite fermions has
extensively been studied in the present literature, this paper is concerned
with maximally entangled fermions. A complete characterization of maximally
entangled quasifree (gaussian) fermion states is given in terms of the
covariance matrix. This result can be seen as a step towards distillation
protocols for maximally entangled fermions.Comment: 13 pages, 1 figure, RevTex, minor errors are corrected, section
"Conclusions" is adde
Porous Ceramic Bodies with Interconnected Pore Channels by a Novel Freeze Casting Technique
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66223/1/j.1551-2916.2005.00176.x.pd
Influence of second-order corrections to the energy-dependence of neutrino flavor conversion formulae
We discuss the {\em intermediate} wave-packet formalism for analytically
quantifying the energy dependence of the two-flavor conversion formula that is
usually considered for analyzing neutrino oscillations and adjusting the
focusing horn, target position and/or detector location of some flavor
conversion experiments. Following a sequence of analytical approximations where
we consider the second-order corrections in a power series expansion of the
energy, we point out a {\em residual} time-dependent phase which, in addition
to some well known wave-packet effects, can subtly modify the oscillation
parameters and limits. In the present precision era of neutrino oscillation
experiments where higher precision measurements are required, we quantify some
small corrections in neutrino flavor conversion formulae which lead to a
modified energy-dependence for oscillations.Comment: 13 pages, 3 figure
Neutrino texture saturating the CP asymmetry
We study a neutrino mass texture which can explain the neutrino oscillation
data and also saturate the upper bound of the CP asymmetry in the
leptogenesis. We consider the thermal and non-thermal leptogenesis based on the
right-handed neutrino decay in this model. A lower bound of the reheating
temperature required for the explanation of the baryon number asymmetry is
estimated as GeV for the thermal leptogenesis and GeV for
the non-thermal one.It can be lower than the upper bound of the reheating
temperature imposed by the cosmological gravitino problem. An example of the
construction of the discussed texture is also presented.Comment: 23 pages, 6 figure
A C-13(alpha,n)O-16 calibration source for KamLAND
We report on the construction and performance of a calibration source for
KamLAND using the reaction C-13(alpha,n)O-16 with Po-210 as the alpha
progenitor. The source provides a direct measurement of this background
reaction in our detector, high energy calibration points for the detector
energy scale, and data on quenching of the neutron visible energy in KamLAND
scintillator. We also discuss the possibility of using the reaction
C-13(alpha,n)O-16 as a source of tagged slow neutrons.Comment: 6 pages, 4 figures. Revised to agree with the published tex
A Kelvin-wave cascade on a vortex in superfluid He at a very low temperature
A study by computer simulation is reported of the behaviour of a quantized
vortex line at a very low temperature when there is continuous excitation of
low-frequency Kelvin waves. There is no dissipation except by phonon radiation
at a very high frequency. It is shown that non-linear coupling leads to a net
flow of energy to higher wavenumbers and to the development of a simple
spectrum of Kelvin waves that is insensitive to the strength and frequency of
the exciting drive. The results are likely to be relevant to the decay of
turbulence in superfluid He at very low temperatures
The H\"older Inequality for KMS States
We prove a H\"older inequality for KMS States, which generalises a well-known
trace-inequality. Our results are based on the theory of non-commutative
-spaces.Comment: 10 page
Particle Redistribution During Dendritic Solidification of Particle Suspensions
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65783/1/j.1551-2916.2006.01094.x.pd
Leptogenesis with Friedberg-Lee Symmetry
We consider the symmetric Friedberg-Lee (FL) symmetry for the
neutrino sector and show that a specific FL translation leads to the
tribimaximal mixing pattern of the Maki-Nakagawa-Sakata (MNS) matrix. We also
apply the symmetry to the type-I seesaw framework and address the baryon
asymmetry of the universe through the leptogenesis mechanism. We try to
establish a relation between the net baryon asymmetry and CP phases included in
the MNS matrix.Comment: Talk given at International Workshop on Dark Matter, Dark Energy and
Matter-Antimatter Asymmetry, Hsinchu, Taiwan, 20-21 Nov. 2009, to be
published in Modern Physics Letters A, reference adde
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