119715420
ABJM theory in Batalin–Vilkovisky formulation
Abstract We analyze the quantum ABJM theory on N = 1 superspace in different gauges. We study the Batalin–Vilkovisky (BV) formulation for this model. By developing field/antifield dependent BRST transformation we establish connection between the two different solutions of the quantum master equation within the BV formulation.
52026932
dS/CFT at uniform energy density and a de Sitter “bluewall”
A bstractWe describe a class of spacetimes that are asymptotically de Sitter in the Poincare slicing. Assuming that a dS/CFT correspondence exists, we argue that these are gravity duals to a CFT on a circle leading to uniform energy-momentum density, and are equivalent to an analytic continuation of the Euclidean AdS black brane. These are solutions with a complex parameter which then gives a real energy-momentum density. We also discuss a related solution with the parameter continued to a real number, which we refer to as a de Sitter “bluewall”. This spacetime has two asymptotic de Sitter universes and Cauchy horizons cloaking timelike singularities. We argue that the Cauchy horizons give rise to a blue-shift instability.
118725297
Double trace flows and holographic RG in dS/CFT correspondence
A bstractIf there is a dS/CFT correspondence, time evolution in the bulk should translate to RG flows in the dual euclidean field theory. Consequently, although the dual field is expected to be non-unitary, its RG flows will carry an imprint of the unitary time evolution in the bulk. In this note we examine the prediction of holographic RG in de Sitter space for the flow of double and triple trace couplings in any proposed dual. We show quite generally that the correct form of the field theory beta functions for the double trace couplings is obtained from holography, provided one identifies the scale of the field theory with (i|T|) where T is the ‘time’ in conformal coordinates. For dS4, we find that with an appropriate choice of operator normalization, it is possible to have real n-point correlation functions as well as beta functions with real coefficients. This choice leads to an RG flow with an IR fixed point at negative coupling unlike in a unitary theory where the IR fixed point is at positive coupling. The proposed correspondence of Sp(N) vector models with de Sitter Vasiliev gravity provides a specific example of such a phenomenon. For dSd+1 with even d, however, we find that no choice of operator normalization exists which ensures reality of coefficients of the beta-functions as well as absence of n-dependent phases for various n-point functions, as long as one assumes real coupling constants in the bulk Lagrangian.
119115082
Quantum quench across a zero temperature holographic superfluid transition
A bstractWe study quantum quench in a holographic model of a zero temperature insulator-superfluid transition. The model is a modification of that of arXiv:0911.0962 and involves a self-coupled complex scalar field, Einstein gravity with a negative cosmological constant, and Maxwell field with one of the spatial directions compact. In a suitable regime of parameters, the scalar field can be treated as a probe field whose backreaction to both the metric and the gauge field can be ignored. We show that when the chemical potential of the dual field theory lies between two critical values, the equilibrium background geometry is an AdS soliton with a constant gauge field, while the complex scalar condenses leading to broken symmetry. We then turn on a time dependent source for the order parameter which interpolates between constant values and crosses the order-disorder critical point. In the critical region adiabaticity breaks down, but for a small rate of change of the source v there is a new small-v expansion in fractional powers of v. The resulting critical dynamics is dominated by a zero mode of the bulk field. To lowest order in this small-v expansion, the order parameter satisfies a time dependent Landau-Ginsburg equation which has z = 2, but non-dissipative. These predictions are verified by explicit numerical solutions of the bulk equations of motion.
119205437
Bi-local construction of Sp(2N)/dS higher spin correspondence
A bstractWe derive a collective field theory of the singlet sector of the Sp(2N) sigma model. Interestingly the Hamiltonian for the bilocal collective field is the same as that of the O(N) model. However, the large-N saddle points of the two models differ by a sign. This leads to a fluctuation Hamiltonian with a negative quadratic term and alternating signs in the nonlinear terms which correctly reproduces the correlation functions of the singlet sector. Assuming the validity of the connection between O(N) collective fields and higher spin fields in AdS, we argue that a natural interpretation of this theory is by a double analytic continuation, leading to the dS/CFT correspondence proposed by Anninos, Hartman and Strominger. The bi-local construction gives a map into the bulk of de Sitter space-time. Its geometric pseudospin-representation provides a framework for quantization and definition of the Hilbert space. We argue that this is consistent with finite N Grassmannian constraints, establishing the bi-local representation as a nonperturbative framework for quantization of Higher Spin Gravity in de Sitter space.
118390596
Quantum quench and double trace couplings
A bstractWe consider quantum quench by a time dependent double trace coupling in a strongly coupled large N field theory which has a gravity dual via the AdS/CFT correspondence. The bulk theory contains a self coupled neutral scalar field coupled to gravity with negative cosmological constant. We study the scalar dynamics in the probe approximation in two backgrounds: AdS soliton and AdS black brane. In either case we find that in equilibrium there is a critical phase transition at a negative value of the double trace coupling κ below which the scalar condenses. For a slowly varying homogeneous time dependent coupling crossing the critical point, we show that the dynamics in the critical region is dominated by a single mode of the bulk field. This mode satisfies a Landau-Ginsburg equation with a time dependent mass, and leads to Kibble Zurek type scaling behavior. For the AdS soliton the system is non-dissipative and has z = 1, while for the black brane one has dissipative z = 2 dynamics. We also discuss the features of a holographic model which would describe the non-equilibrium dynamics around quantum critical points with arbitrary dynamical critical exponent z and correlation length exponent ν. These analytical results are supported by direct numerical solutions.
120277549
Exact scalar and spinor solutions in the field of a stationary cosmic string
In this article exact solutions of the Klein–Gordon and Weyl equations in the field of a stationary cosmic string are presented.
119194509
Quarkonia production at forward rapidity in Pb+Pb collisions at ${\sqrt{{s}_{\rm NN}}=2.76}$ TeV with the ALICE detector
The study of formation of heavy quarkonia in relativistic heavy-ion collisions provides important insight into the properties of the produced high-density QCD medium. Lattice QCD studies show sequential suppression of quarkonia states with increasing temperature; which affirms that a full spectroscopy can provide us a thermometer for the matter produced under extreme conditions in relativistic heavy-ion collisions and one of the most direct probes of deconfinement. Muons from the decay of charmonium resonances are detected in ALICE experiment in p + p and Pb+Pb collisions with a muon spectrometer, covering the forward rapidity region (2.5 < y < 4). The analysis of the inclusive J/ψ production in the first Pb+Pb data collected in the fall of 2010 at a centre of mass energy of $\sqrt{s_{\rm NN}}=2.76$ TeV is discussed. Preliminary results on the nuclear modification factor (RAA) and the central to peripheral nuclear modification factor (RCP) are presented.
121418091
Quantum fluctuations near a black-hole singularity
Abstract We present here an investigation of the problem of quantum fluctuations near a black-hole singularity. We show that quantum fluctuations do not vanish near the singularity leading to the conclusion that black-hole singularities are unlikely to exist.
123139058
Conformal freedom and Kasner and Belinskii models
In this paper we show, in the context of the quantum mechanical principle of uncertainty, that if conformal freedom has a quantum character then Kasner and Belinskii models have a status quantum-mechanically different from some models, i.e. Robertson - Walker, Bianchi type I (some forms) and Bianchi type III models.
106403057
Search for a stable alignment limit in two-Higgs-doublet models
We study the conditions required to make the two-Higgs-doublet-model (2HDM) scalar potential stable up to the Planck scale. The lightest CP-even scalar is assumed to have been found at the LHC and the alignment limit is imposed in view of the LHC Higgs data. We find that ensuring stability up to scales 1010GeV necessitates the introduction of a soft breaking parameter in the theory. Even then, some interesting correlations between the nonstandard masses and the soft breaking parameter need to be satisfied. Consequently, a 2HDM becomes completely determined by only two nonstandard parameters, namely, tanβ and a mass parameter, m0, with tanβ3. These observations make a 2HDM, in the stable alignment limit, more predictive than ever.