7,913 research outputs found
More Communication with Less Entanglement
We exhibit the intriguing phenomena of "Less is More" using a set of
multipartite entangled states. We consider the quantum communication protocols
for the {\em exact} teleportation, superdense coding, and quantum key
distribution. We find that sometimes {\em less} entanglement is {\em more}
useful. To understand this phenomena we obtain a condition that a resource
state must satisfy to communicate a -qubit pure state with terms. We
find that the an appropriate partition of the resource state should have a
von-Neumann entropy of . Furthermore, it is shown that some
states may be suitable for exact superdense coding, but not for exact
teleportation.Comment: 7 pages, 1 tabl
Quantum Hall Effect and Semimetallic Behavior of Dual-Gated ABA-Stacked Trilayer Graphene
The electronic structure of multilayer graphenes depends strongly on the
number of layers as well as the stacking order. Here we explore the electronic
transport of purely ABA-stacked trilayer graphenes in a dual-gated field-effect
device configuration. We find that both the zero-magnetic-field transport and
the quantum Hall effect at high magnetic fields are distinctly different from
the monolayer and bilayer graphenes, and that they show electron-hole
asymmetries that are strongly suggestive of a semimetallic band overlap. When
the ABA trilayers are subjected to an electric field perpendicular to the
sheet, Landau level splittings due to a lifting of the valley degeneracy are
clearly observed.Comment: 5 figure
Field Theories on Null Manifolds
We argue that generic field theories defined on null manifolds should have an emergent BMS or conformal Carrollian structure. We then focus on a simple interacting conformal Carrollian theory, viz. Carrollian scalar electrodynamics. We look at weak (on-shell) and strong invariance (off-shell) of its equations of motion under conformal Carrollian symmetries. Helmholtz conditions are necessary and sufficient conditions for a set of equations to arise from a Lagrangian. We investigate whether the equations of motion of Carrollian scalar electrodynamics satisfy these conditions. Then we proposed an action for the electric sector of the theory. This action is the first example for an interacting conformal Carrollian Field Theory. The proposed action respects the finite and infinite conformal Carrollian symmetries in d = 4. We calculate conserved charges corresponding to these finite and infinite symmetries and then rewrite the conserved charges in terms of the canonical variables. We finally compute the Poisson brackets for these charges and confirm that infinite Carrollian conformal algebra is satisfied at the level of charges
How Do Glassy Domains Grow?
We construct the equations for the growth kinetics of a structural glass
within mode-coupling theory, through a non-stationary variant of the 3-density
correlator defined in Phys. Rev. Lett. 97}, 195701 (2006). We solve a schematic
form of the resulting equations to obtain the coarsening of the 3-point
correlator as a function of waiting time . For a quench
into the glass, we find that attains a peak value at
, providing a theoretical basis for the numerical
observations of Parisi [J. Phys. Chem. B 103, 4128 (1999)] and Kob and Barrat
[Phys. Rev. Lett. 78, 4581 (1997)]. The aging is not "simple": the
dependence cannot be attributed to an evolving effective temperature.Comment: 6 pages, 5 figure
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