5243610
Non-Abelian Vortices at Weak and Strong Coupling in Mass Deformed ABJM Theory
We find half-BPS vortex solitons, at both weak and strong coupling, in the = 6 supersymmetric mass deformation of ABJM theory with U(N) × U(N) gauge symmetry and Chern-Simons level k. The strong coupling gravity dual is obtained by performing a k quotient of the = 8 supersymmetric eleven dimensional supergravity background of Lin, Lunin and Maldacena corresponding to the mass deformed M2-brane theory. At weak coupling, the BPS vortices preserving six supersymmetries are found in the Higgs vacuum of the theory where the gauge symmetry is broken to U(1) × U(1). The classical vortex solitons break a colour-flavour locked global symmetry resulting in non-Abelian internal orientational moduli and a CP1 moduli space of solutions. At strong coupling and large k, upon reduction to type IIA strings, the vortex moduli space and its action are computed by a probe D0-brane in the dual geometry. The mass of the D0-brane matches the classical vortex mass. However, the gravity picture exhibits a six dimensional moduli space of solutions, a section of which can be identified as the CP1 we find classically, along with a Dirac monopole connection of strength k. It is likely that the extra four dimensions in the moduli space are an artifact of the strong coupling limit and of the supergravity approximation.
10546536
Instabilities of the small black hole: a view from N = 4 SYM
We compute a one-loop effective action for the constant modes of the scalars and the Polyakov loop matrix of = 4 SYM on S3 at finite temperature and weak 't Hooft coupling. Above a critical temperature, the effective potential develops new unstable directions accompanied by new saddle points which only preserve an SO(5) subgroup of the SO(6) global R-symmetry. We identify this phenomenon as the weak coupling version of the well known Gregory-Laflamme localization instability in the gravity dual of the strongly coupled field theory: The small AdS5 black hole when viewed as a ten dimensional, asymptotically AdS5 × S5 solution smeared on the S5 is unstable to localization on S5. Our effective potential, in a specific Lorentzian continuation, can provide a qualitative holographic description of the decay of the ``topological black hole'' into the AdS bubble of nothing.
14488849
Inflaton decay in de Sitter spacetime
We study the decay of scalar fields, in particular the inflaton, into lighter scalars in a de Sitter spacetime background. After providing a practical definition of the rate, we focus on the case of an inflaton interacting with a massless scalar field either minimally or conformally coupled to the curvature. The evolution equation for the expectation value of the inflaton is obtained to one loop order in perturbation theory and the decay rate is recognized from the solution. We find the remarkable result that this decay rate displays an equilibrium Bose-enhancement factor with an effective temperature given by the Hawking temperature H/2{pi}, where H is the Hubble constant. This contribution is interpreted as the {open_quotes}stimulated emission{close_quotes} of bosons in a thermal bath at the Hawking temperature. In the context of new inflation scenarios, we show that inflaton decay into conformally coupled massless fields slows down the rolling of the expectation value. Decay into Goldstone bosons is also studied. Contact with stochastic inflation is established by deriving the Langevin equation for the coarse-grained expectation value of the inflaton field to one-loop order in this model. We find that the noise is Gaussian and correlated (colored) and its correlations are related tomore » the dissipative ({open_quotes}decay{close_quotes}) kernel via a generalized fluctuation-dissipation relation. {copyright} {ital 1997} {ital The American Physical Society}« less
117647469
Non-Equilibrium Dynamics in a New Inflation Model and Cosmological Perturbations
17544914
Precision test of AdS/CFT in Lunin-Maldacena background
We obtain the solutions and explicitly calculate the energy for a class of two-spin semiclassical string states in the Lunin-Maldacena background. These configurations are the β-deformed versions of the folded string solutions in AdS5 × S5 background. They correspond to certain single trace operators in the = 1 superconformal β deformation of = 4 Yang-Mills. We calculate the one loop anomalous dimension for the dual single trace operators from the associated twisted spin chain with a general two-cut distribution of Bethe roots. Our results show a striking match between the two calculations. We demonstrate the natural identification of parameters on the two sides of the analysis, and explain the significance of the Virasoro constraint associated with the winding motion of semiclassical strings from the perspective of the spin chain solution.
2071005
Spacetime Virasoro algebra from strings on zero radius AdS3
We study bosonic string theory in the light-cone gauge on AdS3 spacetime with zero radius of curvature (in string units) R/(?')1/2 = 0. We find that the worldsheet theory admits an infinite number of conserved quantities which are naturally interpreted as spacetime charges and which form a representation of (two commuting copies of) a Virasoro algebra. Near the boundary of AdS3 these charges are found to be isomorphic to the infinite set of asymptotic Killing vectors of AdS3 found originally by Brown and Henneaux. In addition to the spacetime Virasoro algebra, there is a worldsheet Virasoro algebra that generates diffeomorphisms of the spatial coordinate of the string worldsheet. We find that if the worldsheet Virasoro algebra has a central extension then the spacetime Virasoro algebra acquires a central extension via a mechanism similar to that encountered in the context of the SL(2,) WZW model. Our observations are consistent with a recently proposed duality between bosonic strings on zero radius AdSd+1 and free field theory in d dimensions.
18426911
Two-Zero Symmetric Neutrino Mass Matrices in Minimal Supersymmetric SO(10)
The phenomenological neutrino mass matrix for two-zero symmetric texture has been obtained and used to rule out all possible two-zero symmetric neutrino mass matrices obtained from Yukawa couplings to $\mathbf{10}$ and $\mathbf{126}$ Higgs representations within the framework of minimal supersymmetric SO(10).
118862615
Systematic Study on System Size Dependence of Global Stopping: Role of Momentum-Dependent Interactions and Symmetry Energy
Using the isospin-dependent quantum molecular dynamical (IQMD) model, we systematically study the role of momentum dependent interactions in global stopping and analyze the effect of symmetry energy in the presence of momentum dependent interactions. For this, we simulate the reactions by varying the total mass of the system from 80 to 394 at different beam energies from 30 to 1000 MeV/nucleon over central and semi-central geometries. The study is carried in the presence of momentum dependent interactions and symmetry energy by taking into account hard equation of state. The nuclear stopping is found to be sensitive towards the momentum dependent interactions and symmetry energy at low incident energies. The momentum dependent interactions are found to weaken the finite size effects in nuclear stopping.
119181819
Correlation between balance energy and transition energy for symmetric colliding nuclei
We study the correlation between balance energy and transition energy of fragments in heavy-ion collisions for different systems at incident energies between 40 and 1200 MeV/nucleon using an isospin-dependent quantum molecular dynamics model. With increasing incident energy, the elliptic flow shows a transition from positive (in-plane) to negative (out-of-plane) flow. This transition energy is found to depend on the size of the fragments, composite mass of the reacting system, and the impact parameter of the reaction. It has been observed that a reduced cross section can explain the experimental data. There is a correlation between transition energy and balance energy as their difference decreases with an increase in the total mass of colliding nuclei.
118517206
Boson stars in a theory of complex scalar fields coupled to the U(1) gauge field and gravity
We study boson shells and boson stars in a theory of a complex scalar field coupled to the gauge field and Einstein gravity with the potential . This could be considered either as a theory of a massive complex scalar field coupled to an electromagnetic field and gravity in a conical potential, or as a theory in the presence of a potential that is an overlap of a parabolic and conical potential. Our theory has a positive cosmological constant . Boson stars are found to come in two types, having either ball-like or shell-like charge density. We studied the properties of these solutions and also determined their domains of existence for some specific values of the parameters of the theory. Similar solutions have also been obtained by Kleihaus, Kunz, Laemmerzahl and List, in a V-shaped scalar potential.
9833237
Measurement of the damping of the nuclear shell effect in the doubly magic 208Pb region.
The damping of the nuclear shell effect with excitation energy has been measured through an analysis of the neutron spectra following the triton transfer in the (7)Li induced reaction on (205)Tl. The measured neutron spectra demonstrate the expected large shell correction energy for the nuclei in the vicinity of doubly magic (208)Pb and a small value around (184)W. A quantitative extraction of the allowed values of the damping parameter γ, along with those for the asymptotic nuclear level density parameter ã, has been made for the first time.