minos axenides - Academia.edu (original) (raw)

Papers by minos axenides

arXiv (Cornell University), Aug 28, 2016

We also find that the thermalization of infalling wave packets in this particular model is expone... more We also find that the thermalization of infalling wave packets in this particular model is exponentially fast, thereby saturating the STB, under the constraint that the finite dimension of the single--particle Hilbert space takes values in the set of Fibonacci integers.

Cornell University - arXiv, Aug 5, 2022

We demonstrate the existence of non-abelian non-topological solitons such as Q-balls in the spect... more We demonstrate the existence of non-abelian non-topological solitons such as Q-balls in the spectrum of Wess-Zumino models with non-abelian global symmetries. We conveniently name them Q-superballs and identify them for short as Q-sballs. More specifically, we show that in contrast to the nonsupersymmetric case, they arise in renormalizable potentials with cubic selfinteractions of only one dimensionful parameter and for the entire parameter space of the model available. We solve the field equations and present the explicit form of the Q-sball solution. We compute its main physical properties and observe that in the supersymmetrically invariant vacuum Q-sballs form domains of manifestly broken sypersymmetry. 1

We discuss recent work with E.Floratos (JHEP 1004:036,2010) on Nambu Dynamics of Intersecting Sur... more We discuss recent work with E.Floratos (JHEP 1004:036,2010) on Nambu Dynamics of Intersecting Surfaces underlying Dissipative Chaos in R 3. We present our argument for the well studied Lorenz and Rössler strange attractors. We implement a flow decomposition to their equations of motion. Their volume preserving part preserves in time a family of two intersecting surfaces, the so called Nambu Hamiltonians. For dynamical systems with linear dissipative sector such as the Lorenz system, they are specified in terms of Intersecting Quadratic Surfaces. For the case of the Rössler system, with nonlinear dissipative part, they are given in terms of a Helicoid intersected by a Cylinder. In each case they foliate the entire phase space and get deformed by Dissipation , the irrotational component to their flow. It is given by the gradient of a surface in R 3 specified in terms of a scalar function. All three intersecting surfaces reproduce completely the dynamics of each strange attractor.

Cosmological Parameters -- CMB, SDSS Accelerator Searches for Dark Matter Dark Matter and Galacti... more Cosmological Parameters -- CMB, SDSS Accelerator Searches for Dark Matter Dark Matter and Galactic Dynamics Direct and Indirect Detection Methods Wimps and SuperWimps Supersymmetric Dark Matter Axions and Axion Searches Warm Dark Matter Neutrinos Masses Neutrino Telescopes -- Present Status and Future Prospects Dark Energy Quintessence.

arXiv: High Energy Physics - Theory, 2020

We review our recent work on ellipsoidal M2-brane solutions in the large-N limit of the BMN matri... more We review our recent work on ellipsoidal M2-brane solutions in the large-N limit of the BMN matrix model. These bosonic finite-energy membranes live inside SO(3)xSO(6) symmetric plane-wave spacetimes and correspond to local extrema of the energy functional. They are static in SO(3) and stationary in SO(6). Chaos appears at the level of radial stability analysis through the explicitly derived spectrum of eigenvalues. The angular perturbation analysis is suggestive of the presence of weak turbulence instabilities that propagate from low to high orders in perturbation theory.

We investigate the possibility that the Universe may inflate due to moduli fields, corresponding ... more We investigate the possibility that the Universe may inflate due to moduli fields, corresponding to flat directions of supersymmetry, lifted by supergravity corrections. We show that a period of ‘locked’ inflation, induced by an oscillating inflaton, may well be followed by a stage of fast-roll inflation. We demonstrate that these two consecutive inflationary phases result in enough total e-foldings to encompass the cosmological scales. Using natural values for the parameters (masses of order TeV and vacuum energy of the intermediate scale corresponding to gravity mediated supersymmetry breaking) we conclude that the η-problem of inflation is easily overcome. To generate structure in the Universe we assume the presence of a curvaton field. Finally we also discuss the moduli problem and how it affects our considerations.

Physical Review D, 2021

We study the leading (LO) and the next-to-leading order (NLO) stability of multipole perturbation... more We study the leading (LO) and the next-to-leading order (NLO) stability of multipole perturbations for a static dielectric M2-brane with spherical topology in the 11-dimensional maximally supersymmetric plane-wave background. We observe a cascade of instabilities that originates from the dipole (j = 1) and quadrupole (j = 2) sectors (the only unstable sectors of the LO) and propagates towards all the multipoles of the NLO.

Symmetry, Integrability and Geometry: Methods and Applications, 2021

According to the 't Hooft-Susskind holography, the black hole entropy, S BH , is carried by the c... more According to the 't Hooft-Susskind holography, the black hole entropy, S BH , is carried by the chaotic microscopic degrees of freedom, which live in the near horizon region and have a Hilbert space of states of finite dimension d = exp(S BH). In previous work we have proposed that the near horizon geometry, when the microscopic degrees of freedom can be resolved, can be described by the AdS 2 [Z N ] discrete, finite and random geometry, where N ∝ S BH. It has been constructed by purely arithmetic and group theoretical methods and was studied as a toy model for describing the dynamics of single particle probes of the near horizon region of 4d extremal black holes, as well as to explain, in a direct way, the finiteness of the entropy, S BH. What has been left as an open problem is how the smooth AdS 2 geometry can be recovered, in the limit when N → ∞. In the present article we solve this problem, by showing that the discrete and finite AdS 2 [Z N ] geometry can be embedded in a family of finite geometries, AdS M 2 [Z N ], where M is another integer. This family can be constructed by an appropriate toroidal compactification and discretization of the ambient (2+1)-dimensional Minkowski space-time. In this construction N and M can be understood as "infrared" and "ultraviolet" cutoffs respectively. The above construction enables us to obtain the continuum limit of the AdS M 2 [Z N ] discrete and finite geometry, by taking both N and M to infinity in a specific correlated way, following a reverse process: Firstly, we show how it is possible to recover the continuous, toroidally compactified, AdS 2 [Z N ] geometry by removing the ultraviolet cutoff; secondly, we show how it is possible to remove the infrared cutoff in a specific decompactification limit, while keeping the radius of AdS 2 finite. It is in this way that we recover the standard non-compact AdS 2 continuum space-time. This method can be applied directly to higher-dimensional AdS spacetimes.

Physical Review D, 2018

We explore the stability of a recently found class of spinning dielectric M2-branes in the 11dime... more We explore the stability of a recently found class of spinning dielectric M2-branes in the 11dimensional maximally supersymmetric plane-wave background. We find two small windows of instabilities in the dipole (j = 1) and quadrupole (j = 2) sector of linear multipole perturbations.

The European Physical Journal C, 2018

Based on our recent work on the discretization of the radial AdS 2 geometry of extremal BH horizo... more Based on our recent work on the discretization of the radial AdS 2 geometry of extremal BH horizons, we present a toy model for the chaotic unitary evolution of infalling single-particle wave packets. We construct explicitly the eigenstates and eigenvalues for the single-particle dynamics for an observer falling into the BH horizon, with as time evolution operator the quantum Arnol'd cat map (QACM). Using these results we investigate the validity of the eigenstate thermalization hypothesis (ETH), as well as that of the fast scrambling time bound (STB). We find that the QACM, while possessing a linear spectrum, has eigenstates, which are random and satisfy the assumptions of the ETH. We also find that the thermalization of infalling wave packets in this particular model is exponentially fast, thereby saturating the STB, under the constraint that the finite dimension of the single-particle Hilbert space takes values in the set of Fibonacci integers.

Physics Letters B, 2017

We investigate the large-N limit of the BMN matrix model by analyzing the dynamics of ellipsoidal... more We investigate the large-N limit of the BMN matrix model by analyzing the dynamics of ellipsoidal M2-branes that spin in the 11-dimensional maximally supersymmetric SO(3) × SO(6) plane-wave background. We identify finite-energy solutions by specifying the local minima of the corresponding energy functional. These configurations are static in SO(3) due to the Myers effect and rotate in SO(6) with an angular momentum that is bounded from above. As a first step towards studying their chaotic properties, we evaluate the Lyapunov exponents of their radial fluctuations.

Nuclear Physics B, 2016

A new infinite-size limit of strings in R × S 2 is presented. The limit is obtained from single s... more A new infinite-size limit of strings in R × S 2 is presented. The limit is obtained from single spike strings by letting the angular velocity parameter ω become infinite. We derive the energy-momenta relation of ω = ∞ single spikes as their linear velocity v → 1 and their angular momentum J → 1. Generally, the v → 1, J → 1 limit of single spikes is singular and has to be excluded from the spectrum and be studied separately. We discover that the dispersion relation of omega-infinity single spikes contains logarithms in the limit J → 1. This result is somewhat surprising, since the logarithmic behavior in the string spectra is typically associated with their motion in non-compact spaces such as AdS. Omega-infinity single spikes seem to completely cover the surface of the 2-sphere they occupy, so that they may essentially be viewed as some sort of "brany strings". A proof of the sphere-filling property of omega-infinity single spikes is given in the appendix.

We review recent work on a new class of topological defects which possess a nonsymmetric core. Th... more We review recent work on a new class of topological defects which possess a nonsymmetric core. They arise in scalar field theories with global symmetries, U(1) for domain walls and SU(2) for vortices, which are explicitly broken to Z 2 and U(1) respectively. Both of the latter symmetries are spontaneously broken. For a particular range of parameters both types of defect solutions are shown to become unstable and decay to the well known stable walls and vortices with symmetric cores.

Eprint Arxiv Hep Ph 0111354, Nov 27, 2001

Semitopological Vortices (Q-Rings) are identified to be classical soliton configurations whose st... more Semitopological Vortices (Q-Rings) are identified to be classical soliton configurations whose stability is attributed to both topological and nontopological charges. We discuss some recent work on the simplest possible realization of such a configuration in a scalar field theory with an unbroken U (1) global symmetry. We show that Q-Rings correspond to local minima of the energy, exhibit numerical solutions of their field configurations and derive virial theorems demonstrating their stability.

Vortices in superfluid 3He-B have been observed to undergo a core transition. We discuss the anal... more Vortices in superfluid 3He-B have been observed to undergo a core transition. We discuss the analog phenomenon in relativistic field theories which admit embedded global domain walls, vortices and monopoles with a core phase structure. They are present in scalar field theories with approximate global symmetries which are broken both spontaneously and in parts explicitly. For a particular range of parameters their symmetric core exhibits an instability and decays into the nonsymmetric phase.