1,342,006 research outputs found
An evaluation of the analytic continuation by duality technique
In Nucl. Phys. B391 (1993) 127, the value of the oblique correction parameter
S for walking technicolor theories was estimated using a technique called
Analytic Continuation by Duality (ACD). We apply the ACD technique to the
perturbative vacuum polarization function and find that it fails to reproduce
the well known result S=1/6\pi. This brings into question the reliability of
the ACD technique and the ACD estimate of S.Comment: 8 pages, LaTeX, 1 postscript figure. Uses cite.sty, sprocl.sty, and
epsfig.sty. Talk presented at the 1996 International Workshop on Perspectives
of Strong Coupling Gauge Theories (SCGT'96), 13-16 Nov. 1996, Nagoy
The K Band Luminosity Functions of Galaxies in High Redshift Clusters
K band luminosity functions (LFs) of three, massive, high redshift clusters
of galaxies are presented. The evolution of K*, the characteristic magnitude of
the LF, is consistent with purely passive evolution, and a redshift of forma
tion z = 1.5-2.Comment: 3 pages, to appear in Proceedings of IAU Colloquium 195 - Outskirts
of Galaxy Clusters: intense life in the suburb
Clustering in Hilbert space of a quantum optimization problem
The solution space of many classical optimization problems breaks up into
clusters which are extensively distant from one another in the Hamming metric.
Here, we show that an analogous quantum clustering phenomenon takes place in
the ground state subspace of a certain quantum optimization problem. This
involves extending the notion of clustering to Hilbert space, where the
classical Hamming distance is not immediately useful. Quantum clusters
correspond to macroscopically distinct subspaces of the full quantum ground
state space which grow with the system size. We explicitly demonstrate that
such clusters arise in the solution space of random quantum satisfiability
(3-QSAT) at its satisfiability transition. We estimate both the number of these
clusters and their internal entropy. The former are given by the number of
hardcore dimer coverings of the core of the interaction graph, while the latter
is related to the underconstrained degrees of freedom not touched by the
dimers. We additionally provide new numerical evidence suggesting that the
3-QSAT satisfiability transition may coincide with the product satisfiability
transition, which would imply the absence of an intermediate entangled
satisfiable phase.Comment: 11 pages, 6 figure
Monitoring currents in cold-atom circuits
Complex circuits of cold atoms can be exploited to devise new protocols for
the diagnostics of cold-atoms systems. Specifically, we study the quench
dynamics of a condensate confined in a ring-shaped potential coupled with a
rectilinear guide of finite size. We find that the dynamics of the atoms inside
the guide is distinctive of the states with different winding numbers in the
ring condensate. We also observe that the depletion of the density, localized
around the tunneling region of the ring condensate, can decay in a pair of
excitations experiencing a Sagnac effect. In our approach, the current states
of the condensate in the ring can be read out by inspection of the rectilinear
guide only, leaving the ring condensate minimally affected by the measurement.
We believe that our results set the basis for definition of new quantum
rotation sensors. At the same time, our scheme can be employed to explore
fundamental questions involving dynamics of bosonic condensates.Comment: Figures are enlarged. Section IV is added. Journal reference adde
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