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A. Mironov

Publications and source records attributed to A. Mironov.

At least 217 records · Page 12Linked to original sources
arXiv2007

If LHC is a Mini-Time-Machines Factory, Can We Notice?

Assuming the hypothesis of TeV-scale multi-dimensional gravity, one can imagine that at LHC not only mini-black-holes (MBH) will be intensively created, but also other exotic gravitational configurations, including hypothetical mini-time-machines (MTM). Like MBH, they should quickly evaporate, but one can wonder if their temporal existence at the moment of high-energy collision can leave any traces in the observable data. We briefly discuss five thinkable effects: (i) change of the energy spectrum due to the frequency-filtration property of MTM, (ii) possible production of anomalously energetic particles, accelerated by passing many times through gravitational field inside the MTM, (iii) acceleration of particle decays, since the proper time of a particle moving inside MTM can strongly exceed the laboratory time, (iv) CPT and naive unitarity violation (thermalization) due to effective non-local interactions caused by MTM and to possible ambiguity in the population of closed world-lines inside MTM, (v) collective effects due to conversion of a single particle into a bunch of its co-existing copies within the MTM. Despite possible particle-antiparticle conversion inside MTM, they do not seem to produce any specific CP-violation effects.

hep-th↗
arXiv2007

On n-point Amplitudes in N=4 SYM

The computation of n-point planar amplitudes in N=4 SYM at strong coupling is known to be reduced to the search for solutions of the integrable 2d SO(4,2) sigma-model with growing asymptotics on the world-sheet and to the study of their Whitham deformations induced by an epsilon-regularization, which breaks both integrability and SO(4,2) symmetry. A multi-parameter (moduli) family of such solutions is constructed for n=4. They all correspond to the same s and t and some are related by SO(4,2) transformations. Nevertheless, they lead to different regularized areas, whose minimum is the Alday-Maldacena solution. A brief review of results on n-point amplitudes is also provided, with special emphasis on the underlying equivalence of the above regularized minimal area in AdS and a double contour integral along the same boundary, two purely geometric quantities.

hep-th↗
arXiv2007

Radiation Beyond Four Space-Time Dimensions

We present a list of formulas describing classical radiation of the rank s tensor field from an accelerated point-like source in flat space-time of arbitrary even dimension d. This allows straightforward evaluating the total intensity and radiated momentum for any $s$ and $d$ algorithmically, by hands or with the help of a computer (e.g. with an attached MAPLE program). Practical application of formulas is limited, because, for s>1, the energy-momentum tensor for the point-like source is not conserved. This usually means that one cannot neglect contributions to radiation from tensions of the forces that cause acceleration of the source.

hep-th↗
arXiv2006

Is Strong Gravitational Radiation predicted by TeV-Gravity?

In TeV-gravity models the gravitational coupling to particles with energies E\sim m_{Pl} \sim 10 TeV is not suppressed by powers of ultra-small ratio E/M_{Pl} with M_{Pl} \sim 10^{19} GeV. Therefore one could imagine strong synchrotron radiation of gravitons by the accelerating particles to become the most pronounced manifestation of TeV-gravity at LHC. However, this turns out to be not true: considerable damping continues to exist, only the place of E/M_{Pl} it taken by a power of a ratio θω/E, where the typical frequency ωof emitted radiation, while increased by a number of γ-factors, can not reach E/\vartheta unless particles are accelerated by nearly critical fields. Moreover, for currently available magnetic fields B \sim 10 Tesla, multi-dimensionality does not enhance gravitational radiation at all even if TeV-gravity is correct.

hep-ph↗
arXiv2006

Instantons and Merons in Matrix Models

Various branches of matrix model partition function can be represented as intertwined products of universal elementary constituents: Gaussian partition functions Z_G and Kontsevich tau-functions Z_K. In physical terms, this decomposition is the matrix-model version of multi-instanton and multi-meron configurations in Yang-Mills theories. Technically, decomposition formulas are related to representation theory of algebras of Krichever-Novikov type on families of spectral curves with additional Seiberg-Witten structure. Representations of these algebras are encoded in terms of "the global partition functions". They interpolate between Z_G and Z_K associated with different singularities on spectral Riemann surfaces. This construction is nothing but M-theory-like unification of various matrix models with explicit and representative realization of dualities.

hep-th↗
arXiv2006

M-Theory of Matrix Models

Small M-theories unify various models of a given family in the same way as the M-theory unifies a variety of superstring models. We consider this idea in application to the family of eigenvalue matrix models: their M-theory unifies various branches of Hermitean matrix model (including Dijkgraaf-Vafa partition functions) with Kontsevich tau-function. Moreover, the corresponding duality relations look like direct analogues of instanton and meron decompositions, familiar from Yang-Mills theory.

hep-th↗
arXiv2005

Matrix Models vs. Matrix Integrals

In a brief review, we discuss interrelations between arbitrary solutions of the loop equations that describe Hermitean one-matrix model and particular (multi-cut) solutions that describe concrete matrix integrals. These latter ones enjoy a series of specific properties and, in particular, are described in terms of Seiberg-Witten-Whitham theory. The simplest example of ordinary integral is considered in detail.

hep-th↗
arXiv2005

Complex Geometry of Matrix Models

The paper contains some new results and a review of recent achievements, concerning the multisupport solutions to matrix models. In the leading order of the 't Hooft expansion for matrix integral, these solutions are described by quasiclassical or generalized Whitham hierarchies and are directly related to the superpotentials of four-dimensional N=1 SUSY gauge theories. We study the derivatives of tau-functions for these solutions, associated with the families of Riemann surfaces (with possible double points), and relations for these derivatives imposed by complex geometry, including the WDVV equations. We also find the free energy in subleading order of the 't Hooft expansion and prove that it satisfies certain determinant relations.

hep-th↗
arXiv2005

On the Need for Phenomenological Theory of P-Vortices or Does Spaghetti Confinement Pattern Admit Condensed-Matter Analogies?

Usually the intuition from condensed-matter physics is used to provide ideas for possible confinement mechanisms in gauge theories. Today, with a clear but puzzling ``spaghetti'' confinement pattern, arising after a decade of lattice computer experiments, which implies formation of a fluctuating net of peculiar magnetic vortices rather than condensation of the homogeneously distributed magnetic monopoles, the time is coming to reverse the logic and search for similar patterns in condensed matter systems. The main thing to look for in a condensed matter setup is the simultaneous existence of narrow tubes ($P$-vortices or 1-branes) of direction-changing electric field and broader tubes (Abrikosov lines) of magnetic field, a pattern dual to the one, presumably underlying confinement in gluodynamics. As a possible place for this search we suggest systems with coexisting charge-density waves and superconductivity.

hep-th↗
arXiv2005

Unitary matrix integrals in the framework of Generalized Kontsevich Model. I. Brezin-Gross-Witten Model

We advocate a new approach to the study of unitary matrix models in external fields which emphasizes their relationship to Generalized Kontsevich Models (GKM) with non-polynomial potentials. For example, we show that the partition function of the Brezin-Gross-Witten Model (BGWM), which is defined as an integral over unitary $N\times N$ matrices, $\int [dU] e^{\rm{Tr}(J^\dagger U + JU^\dagger)}$, can also be considered as a GKM with potential ${\cal V}(X) = \frac{1}{X}$. Moreover, it can be interpreted as the generating functional for correlators in the Penner model. The strong and weak coupling phases of the BGWM are identified with the "character" (weak coupling) and "Kontsevich" (strong coupling) phases of the GKM, respectively. This sort of GKM deserves classification as $p=-2$ one (i.e. $c=28$ or $c=-2$) when in the Kontsevich phase. This approach allows us to further identify the Harish-Chandra-Itzykson-Zuber (IZ) integral with a peculiar GKM, which arises in the study of $c=1$ theory and, further, with a conventional 2-matrix model which is rewritten in Miwa coordinates. Inspired by the considered unitary matrix models, some further extensions of the GKM treatment which are inspired by the unitary matrix models which we have considered are also developed. In particular, as a by-product, a new simple method of fixing the Ward identities for matrix models in an external field is presented.

hep-th↗
arXiv2004

Solving Virasoro Constraints in Matrix Models

This is a brief review of recent progress in constructing solutions to the matrix model Virasoro equations. These equations are parameterized by a degree n polynomial W_n(x), and the general solution is labeled by an arbitrary function of n-1 coefficients of the polynomial. We also discuss in this general framework a special class of (multi-cut) solutions recently studied in the context of \cal N=1 supersymmetric gauge theories.

hep-th↗
arXiv2004

Unified description of correlators in non-Gaussian phases of Hermitean matrix model

Following the program, proposed in hep-th/0310113, of systematizing known properties of matrix model partition functions (defined as solutions to the Virasoro-like sets of linear differential equations), we proceed to consideration of non-Gaussian phases of the Hermitean one-matrix model. A unified approach is proposed for description of "connected correlators" in the form of the phase-independent "check-operators" acting on the small space of T-variables (which parameterize the polynomial W(z)). With appropriate definitions and ordering prescriptions, the multidensity check-operators look very similar to the Gaussian case (however, a reliable proof of suggested explicit expressions in all loops is not yet available, only certain consistency checks are performed).

hep-th↗
arXiv2003

N=1 SUSY inspired Whitham prepotentials and WDVV

This brief review deals with prepotentials inspired by N=1 SUSY considerations due to Cachazo, Intrilligator, Vafa. These prepotentials associated with matrix models following Dijkgraaf and Vafa should be considered as given on an enlarged moduli space that includes Whitham times (couplings of the superpotential). This moduli space is nothing but the whole moduli space of (decorated) hyperelliptic curves. Corresponding prepotentials are logarithms of (quasiclassical) tau-functions and satisfy the WDVV equations.

hep-th↗
arXiv2003

DV and WDVV

We prove that the quasiclassical tau-function of the multi-support solutions to matrix models, proposed recently by Dijkgraaf and Vafa to be related to the Cachazo-Intrilligator-Vafa superpotentials of the N=1 supersymmetric Yang-Mills theories, satisfies the Witten-Dijkgraaf-Verlinde-Verlinde equations.

hep-th↗
arXiv2002

Matrix models vs. Seiberg-Witten/Whitham theories

We discuss the relation between matrix models and the Seiberg--Witten type (SW) theories, recently proposed by Dijkgraaf and Vafa. In particular, we prove that the partition function of the Hermitean one-matrix model in the planar (large $N$) limit coincides with the prepotential of the corresponding SW theory. This partition function is the logarithm of a Whitham $τ$-function. The corresponding Whitham hierarchy is explicitly constructed. The double-point problem is solved.

hep-th↗
arXiv2002

MgB2 single crystals: high pressure growth and anisotropic properties

Single crystals of MgB2 with a size up to 1.5x0.9x0.2 mm3 have been grown with a high pressure cubic anvil technique. The crystal growth process is very peculiar and involves an intermediate nitride, namely MgNB9. Single crystals of BN and MgB2 grow simultaneously by a peritectic decomposition of MgNB9. Magnetic measurements in fields of 1-5 Oe show sharp transitions to the superconducting state at 37-38.6 K with width of ~0.5 K. The high quality of the crystals allowed the accurate determination of magnetic, transport and optical properties as well as scanning tunnelling spectroscopy (STS) and decoration studies. Investigations of crystals with torque magnetometry show that Hc2//c is very low (24 kOe at 15 K), while Hc2//ab increases up to 140 kOe at 15 K. The upper critical field anisotropy gamma = Hc2//ab/ Hc2//c was found to be temperature dependent (decreasing from 6 at 15 K to 2.8 at 35 K). The effective anisotropy gamma_eff, as calculated from reversible torque data near Tc, is field dependent (increasing roughly linearly from 2 in zero field to 3.7 in 10 kOe). The temperature and field dependence of the anisotropy can be related to the double gap structure of MgB2 with a large two-dimensional gap and small three-dimensional gap, the latter being rapidly suppressed in a magnetic field. Torque magnetometry investigations show a pronounced peak effect, indicating an order-disorder transition of vortex matter. Decoration experiments and STS visualise a hexagonal vortex lattice. STS spectra evidence two gaps (3 meV/6 meV) with direction dependent weight. Magneto-optic investigations with H//c show a clear signature of the smaller of the two gaps, disappearing in fields higher than Hc2//c.

cond-mat.supr-con↗
arXiv2002

Integrability in string/field theories and Hamiltonian Flows in the Space of Physical Systems

Integrability in string/field theories is known to emerge when considering dynamics in the moduli space of physical theories. This implies that one has to look at the dynamics with respect to unusual time variables like coupling constants or other quantities parameterizing configuration space of physical theories. The dynamics given by variations of coupling constants can be considered as a canonical transformation or, infinitesimally, a Hamiltonian flow in the space of physical systems. We briefly consider here an example of mechanical integrable systems. Then, any function $T(\vec p, \vec q)$ generates a one-parametric family of integrable systems in vicinity of a single system. For integrable system with several coupling constants the corresponding "Hamiltonians" $T_i(\vec p, \vec q)$ satisfy Whitham equations and after quantization (of the original system) become operators satisfying the zero-curvature condition in the space of coupling constants: $$ [\frac{\partial}{\partial g_a} - \hat T_a(\hat{\vec p},\hat{\vec q}),\ \frac{\partial}{\partial g_b} - \hat T_b(\hat{\vec p},\hat{\vec q})] = 0 $$

hep-th↗