37,309 research outputs found
Eigenvalues of Ruijsenaars-Schneider models associated with root system in Bethe ansatz formalism
Ruijsenaars-Schneider models associated with root system with a
discrete coupling constant are studied. The eigenvalues of the Hamiltonian are
givein in terms of the Bethe ansatz formulas. Taking the "non-relativistic"
limit, we obtain the spectrum of the corresponding Calogero-Moser systems in
the third formulas of Felder et al [20].Comment: Latex file, 25 page
Detection of Minimum-Ionizing Particles and Nuclear Counter Effect with Pure BGO and BSO Crystals with Photodiode Read-out
Long BGO (Bismuth Germanate) and BSO (Bismuth Silicate) crystals coupled with
silicon photodiodes have been used to detect minimum-ionizing particles(MIP).
With a low noise amplifier customized for this purpose, the crystals can detect
MIPs with an excellent signal-to-noise ratio. The NCE(Nuclear Counter Effect}
is also clearly observed and measured. Effect of full and partial wrapping of a
reflector around the crystal on light collection is also studied.Comment: 18 pages, including 5 figures; LaTeX and EP
Constructing entanglement witnesses for infinite-dimensional systems
It is shown that, every entangled state in an infinite-dimensional composite
system has a simple entanglement witness of the form with
a nonnegative number and a finite rank self-adjoint operator. We also
provide two methods of constructing entanglement witness and apply them to
obtain some entangled states that cannot be detected by the PPT criterion and
the realignment criterion.Comment: 15 page
Quantum criticality in a double quantum-dot system
We discuss the realization of the quantum-critical non-Fermi liquid state,
originally discovered within the two-impurity Kondo model, in double
quantum-dot systems. Contrary to the common belief, the corresponding fixed
point is robust against particle-hole and various other asymmetries, and is
only unstable to charge transfer between the two dots. We propose an
experimental set-up where such charge transfer processes are suppressed,
allowing a controlled approach to the quantum critical state. We also discuss
transport and scaling properties in the vicinity of the critical point.Comment: 4 pages, 3 figs; (v2) final version as publishe
A characterization of positive linear maps and criteria of entanglement for quantum states
Let and be (finite or infinite dimensional) complex Hilbert spaces. A
characterization of positive completely bounded normal linear maps from
into is given, which particularly gives a
characterization of positive elementary operators including all positive linear
maps between matrix algebras. This characterization is then applied give a
representation of quantum channels (operations) between infinite-dimensional
systems. A necessary and sufficient criterion of separability is give which
shows that a state on is separable if and only if
for all positive finite rank elementary operators
. Examples of NCP and indecomposable positive linear maps are given and
are used to recognize some entangled states that cannot be recognized by the
PPT criterion and the realignment criterion.Comment: 20 page
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