311 research outputs found
Quasinormal modes and Stability Analysis for 4-dimensional Lifshitz Black Hole
We study the Lifshitz black hole in 4-dimensions with dynamical exponent z=2
and we calculate analytically the quasinormal modes of scalar perturbations.
These quasinormal modes allows to study the stability of the Lifshitz black
hole and we have obtained that Lifshitz black hole is stable.Comment: 7 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1205.058
Identification of the proteins, including MAGEG1, that make up the human SMC5-6 protein complex
The SMC protein complexes play important roles in chromosome dynamics. The function of the SMC5-6 complex remains unclear, though it is involved in resolution of different DNA structures by recombination. We have now identified and characterized the four non-SMC components of the human complex and in particular demonstrated that the MAGEG1 protein is part of this complex. MAGE proteins play important but as yet undefined roles in carcinogenesis, apoptosis, and brain development. We show that, with the exception of the SUMO ligase hMMS21/hNSE2, depletion of any of the components results in degradation of all the other components. Depletion also confers sensitivity to methyl methanesulfonate. Several of the components are modified by sumoylation and ubiquitination
Ipl1/Aurora B kinase coordinates synaptonemal complex disassembly with cell cycle progression and crossover formation in budding yeast meiosis
Several protein kinases collaborate to orchestrate and integrate cellular and chromosomal events at the G2/M transition in both mitotic and meiotic cells. During the G2/M transition in meiosis, this includes the completion of crossover recombination, spindle formation, and synaptonemal complex (SC) breakdown. We identified Ipl1/Aurora B kinase as the main regulator of SC disassembly. Mutants lacking Ipl1 or its kinase activity assemble SCs with normal timing, but fail to dissociate the central element component Zip1, as well as its binding partner, Smt3/SUMO, from chromosomes in a timely fashion. Moreover, lack of Ipl1 activity causes delayed SC disassembly in a cdc5 as well as a CDC5-inducible ndt80 mutant. Crossover levels in the ipl1 mutant are similar to those observed in wild type, indicating that full SC disassembly is not a prerequisite for joint molecule resolution and subsequent crossover formation. Moreover, expression of meiosis I and meiosis II-specific B-type cyclins occur normally in ipl1 mutants, despite delayed formation of anaphase I spindles. These observations suggest that Ipl1 coordinates changes to meiotic chromosome structure with resolution of crossovers and cell cycle progression at the end of meiotic prophase
Gravity Dual of Gauge Theory on S^2 x S^1 x R
We (numerically) construct new static, asymptotically AdS solutions where the
conformal infinity is the product of time and S^2 x S^1. There always exist a
family of solutions in which the S^1 is not contractible and, for small S^1,
there are two additional families of solutions in which the S^1 smoothly
pinches off. This shows that (when fermions are antiperiodic around the S^1)
there is a quantum phase transition in the gauge theory as one decreases the
radius of the S^1 relative to the S^2. We also compare the masses of our
solutions and argue that the one with lowest mass should minimize the energy
among all solutions with conformal boundary S^2 x S^1 x R. This provides a new
positive energy conjecture for asymptotically locally AdS metrics. A simple
analytic continuation produces AdS black holes with topology S^2 x S^1.Comment: 17 pages, 4 figures, v2: minor changes, added reference
Diversity, urban space and the right to the provincial city
Using three vignettes of the same physical space this article contributes to understanding of how the right to the city is contested in provincial England in the early twenty-first century. Oral history and ethnographic material gathered in Peterborough between 2010 and 2012 are drawn on to shed new light on the politics of diversity and urban space. This highlights the multiple place attachments and trans-spatial practices of all residents, including the white ethnic majority, as well as contrasting forms of active intervention in space with their different temporalities and affective intensities. The article carries its own diversity politics, seeking to reduce the harm done by racism through challenging the normalisation of the idea of a local, indigenous population, left out by multiculturalism. It simultaneously raises critical questions about capitalist regeneration strategies in terms of their impact both on class inequality and on the environment
Large N Field Theory and AdS Tachyons
In non-supersymmetric orbifolds of N =4 super Yang-Mills, conformal
invariance is broken by the logarithmic running of double-trace operators -- a
leading effect at large N. A tachyonic instability in AdS_5 has been proposed
as the bulk dual of double-trace running. In this paper we make this
correspondence more precise. By standard field theory methods, we show that the
double-trace beta function is quadratic in the coupling, to all orders in
planar perturbation theory. Tuning the double-trace coupling to its (complex)
fixed point, we find conformal dimensions of the form 2 + i b, as formally
expected for operators dual to bulk scalars that violate the stability bound.
We also show that conformal invariance is broken in perturbation theory if and
only if dynamical symmetry breaking occurs. Our analysis is applicable to a
general large N field theory with vanishing single-trace beta functions.Comment: 26 pages, 6 figures. v3: small changes, version published on JHEP
Scalability of quantum computation with addressable optical lattices
We make a detailed analysis of error mechanisms, gate fidelity, and
scalability of proposals for quantum computation with neutral atoms in
addressable (large lattice constant) optical lattices. We have identified
possible limits to the size of quantum computations, arising in 3D optical
lattices from current limitations on the ability to perform single qubit gates
in parallel and in 2D lattices from constraints on laser power. Our results
suggest that 3D arrays as large as 100 x 100 x 100 sites (i.e.,
qubits) may be achievable, provided two-qubit gates can be performed with
sufficiently high precision and degree of parallelizability. Parallelizability
of long range interaction-based two-qubit gates is qualitatively compared to
that of collisional gates. Different methods of performing single qubit gates
are compared, and a lower bound of is determined on the
error rate for the error mechanisms affecting Cs in a blue-detuned
lattice with Raman transition-based single qubit gates, given reasonable limits
on experimental parameters.Comment: 17 pages, 5 figures. Accepted for publication in Physical Review
Black strings with negative cosmological constant: inclusion of electric charge and rotation
We generalize the vacuum static black strings with negative cosmological
constant recently discussed in literature, by including an electromagnetic
field. These higher-dimensional configurations have no dependence on the
`compact' extra dimension, and their boundary topology is the product of time
and or . Rotating generalizations of the
even dimensional black string configurations are considered as well. Different
from the static, neutral case, no regular limit is found for a vanishing event
horizon radius. We explore numerically the general properties of such solutions
and, using a counterterm prescription, we compute their conserved charges and
discuss their thermodynamics. We find that the thermodynamics of the black
strings follows the pattern of the corresponding black hole solutions in AdS
backgrounds.Comment: 35 pages, 8 figures, final versio
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