3,352 research outputs found
Implementation of quantum algorithms with resonant interactions
We propose a scheme for implementing quantum algorithms with resonant
interactions. Our scheme only requires resonant interactions between two atoms
and a cavity mode, which is simple and feasible. Moreover, the implementation
would be an important step towards the fabrication of quantum computers in
cavity QED system.Comment: 4 pages, 3 figure
From insulator to quantum Hall liquid at low magnetic fields
We have performed low-temperature transport measurements on a GaAs
two-dimensional electron system at low magnetic fields. Multiple
temperature-independent points and accompanying oscillations are observed in
the longitudinal resistivity between the low-field insulator and the quantum
Hall (QH) liquid. Our results support the existence of an intermediate regime,
where the amplitudes of magneto-oscillations can be well described by
conventional Shubnikov-de Haas theory, between the low-field insulator and QH
liquid.Comment: Magneto-oscillations governed by Shubnikov-de Haas theory are
observed between the low-field insulator and quantum Hall liqui
Kinetic energy driven superconductivity in the electron doped cobaltate NaCoOHO
Within the charge-spin separation fermion-spin theory, we have shown that the
mechanism of superconductivity in the electron doped cobaltate
NaCoOHO is ascribed to its kinetic energy. The dressed
fermions interact occurring directly through the kinetic energy by exchanging
magnetic excitations. This interaction leads to a net attractive force between
dressed fermions, then the electron Cooper pairs originating from the dressed
fermion pairing state are due to the charge-spin recombination, and their
condensation reveals the superconducting ground state. The superconducting
transition temperature is identical to the dressed fermion pair transition
temperature, and is suppressed to a lower temperature due to the strong
magnetic frustration. The optimal superconducting transition temperature occurs
in the electron doping concentration , and then decreases
for both underdoped and overdoped regimes, in qualitative agreement with the
experimental results.Comment: 6 pages, 2 figs, corrected typos, accepted for publication in Commun.
Theor. Phy
Non-Abelian Collective Excitations in Unlinearized Quark-Gluon Plasma Media
We study the effect of unlinearized medium on the collective excitations in
quark-gluon plasma. We present two kinds of non-Abelian oscillation solutions
which respectively correspond to weakly and strongly nonlinear coupling of
field components in color space. We also show that the weakly nonlinear
solution is similar to Abelian-like one but has the frequency shift, which is
of order , from eigenfrequency.Comment: 7 page
Necessary And Sufficient Condition of Separability of Any System
The necessary and sufficient condition of separability of a mixed state of
any systems is presented, which is practical in judging the separability of a
mixed state. This paper also presents a method of finding the disentangled
decomposition of a separable mixed state.Comment: RevTeX, 5 pages including 1 figure, to appear in Phys. Rev.
Efficient quantum cryptography network without entanglement and quantum memory
An efficient quantum cryptography network protocol is proposed with
d-dimension polarized photons, without resorting to entanglement and quantum
memory. A server on the network, say Alice, provides the service for preparing
and measuring single photons whose initial state are |0>. The users code the
information on the single photons with some unitary operations. For preventing
the untrustworthy server Alice from eavesdropping the quantum lines, a
nonorthogonal-coding technique (decoy-photon technique) is used in the process
that the quantum signal is transmitted between the users. This protocol does
not require the servers and the users to store the quantum state and almost all
of the single photons can be used for carrying the information, which makes it
more convenient for application than others with present technology. We also
discuss the case with a faint laser pulse.Comment: 4 pages, 1 figures. It also presented a way for preparing decoy
photons without a sinigle-photon sourc
Structure optimization in an off-lattice protein model
We study an off-lattice protein toy model with two species of monomers
interacting through modified Lennard-Jones interactions. Low energy
configurations are optimized using the pruned-enriched-Rosenbluth method
(PERM), hitherto employed to native state searches only for off lattice models.
For 2 dimensions we found states with lower energy than previously proposed
putative ground states, for all chain lengths . This indicates that
PERM has the potential to produce native states also for more realistic protein
models. For , where no published ground states exist, we present some
putative lowest energy states for future comparison with other methods.Comment: 4 pages, 2 figure
Colony-forming cells in the adult mouse pancreas are expandable in Matrigel and form endocrine/acinar colonies in laminin hydrogel
The study of hematopoietic colony-forming units using semisolid culture media has greatly advanced the knowledge of hematopoiesis. Here we report that similar methods can be used to study pancreatic colony-forming units. We have developed two pancreatic colony assays that enable quantitative and functional analyses of progenitor-like cells isolated from dissociated adult (2â4 mo old) murine pancreas. We find that a methylcellulose-based semisolid medium containing Matrigel allows growth of duct-like âRing/Denseâ colonies from a rare (âŒ1%) population of total pancreatic single cells. With the addition of roof plate-specific spondin 1, a wingless-int agonist, Ring/Dense colony-forming cells can be expanded more than 100,000-fold when serially dissociated and replated in the presence of Matrigel. When cells grown in Matrigel are then transferred to a Matrigel-free semisolid medium with a unique laminin-based hydrogel, some cells grow and differentiate into another type of colony, which we name âEndocrine/Acinar.â These Endocrine/Acinar colonies are comprised mostly of endocrine- and acinar-like cells, as ascertained by RNA expression analysis, immunohistochemistry, and electron microscopy. Most Endocrine/Acinar colonies contain beta-like cells that secrete insulin/C-peptide in response to D-glucose and theophylline. These results demonstrate robust self-renewal and differentiation of adult Ring/Dense colony-forming units in vitro and suggest an approach to producing beta-like cells for cell replacement of type 1 diabetes. The methods described, which include microfluidic expression analysis of single cells and colonies, should also advance study of pancreas development and pancreatic progenitor cells
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