arXiv subjects

Ryo Suzuki

Publications and source records attributed to Ryo Suzuki.

88 records · Page 5Linked to original sources

arXiv2014

The spectrum of tachyons in AdS/CFT

We analyze the spectrum of open strings stretched between a D-brane and an anti-D-brane in planar AdS/CFT using various tools. We focus on open strings ending on two giant gravitons with different orientation in $AdS_5 \times S^5$ and study the spectrum of string excitations using the following approaches: open spin-chain, boundary asymptotic Bethe ansatz and boundary thermodynamic Bethe ansatz (BTBA). We find agreement between a perturbative high order diagrammatic calculation in ${\cal N}=4$ SYM and the leading finite-size boundary Luscher correction. We study the ground state energy of the system at finite coupling by deriving and numerically solving a set of BTBA equations. While the numerics give reasonable results at small coupling, they break down at finite coupling when the total energy of the string gets close to zero, possibly indicating that the state turns tachyonic. The location of the breakdown is also predicted analytically.

hep-th↗

arXiv2013

Whispering gallery modes in hexagonal microcavities fabricated by crystal growth

We investigated the whispering gallery modes of cavities with a hexagonal cross-section. We found two different modes, namely perturbed and quasi-WGMs, of which the former exhibits the higher Q when the corner radius is large. We studied the dependence of Q on the curvature radius of the polygonal cavities and found that the coupling between the two modes determines the Q of the cavity. In addition we fabricated a cavity by employing laser heated pedestal growth and demonstrated a high Q.

physics.optics↗

arXiv2012

Y-system for Y=0 brane in planar AdS/CFT

The spectrum of open strings with integrable Y=0 brane boundary conditions is analyzed in planar AdS/CFT. We give evidence that it can be described by the same Y-system that governs the spectrum of closed strings in AdS_5xS^5, except with different asymptotic and analytical properties. We determine the asymptotic solution of the Y-system that is consistent both with boundary asymptotic Bethe ansatz and boundary Luscher corrections.

hep-th↗

arXiv2012

Contour deformation trick in hybrid NLIE

The hybrid NLIE of AdS_5 x S^5 is applied to a wider class of states. We find that the Konishi state of the orbifold AdS_5 x (S^5/Z_S) satisfies A_1 NLIE with the source terms which are derived from contour deformation trick. For general states, we construct a deformed contour with which the contour deformation trick yields the correct source terms.

hep-th↗

arXiv2011

Hybrid NLIE for the Mirror AdS_5 x S^5

We revisit the derivation of hybrid nonlinear integral equations of the XXX model starting from the linearization of the T-system related to spinon variables. We obtain two sets of equations, corresponding to two linearly independent solutions of A_1 TQ-relation. Recalling that the TQ-relations in the horizontal strips of the su(2|4|2)-hook is of A_1 type, we replace the corresponding Y-functions by a finite number of auxiliary variables.

hep-th↗

arXiv2010

Exploring the mirror TBA

We apply the contour deformation trick to the Thermodynamic Bethe Ansatz equations for the AdS_5 \times S^5 mirror model, and obtain the integral equations determining the energy of two-particle excited states dual to N=4 SYM operators from the sl(2) sector. We show that each state/operator is described by its own set of TBA equations. Moreover, we provide evidence that for each state there are infinitely-many critical values of 't Hooft coupling constant λ, and the excited states integral equations have to be modified each time one crosses one of those. In particular, estimation based on the large L asymptotic solution gives λ\approx 774 for the first critical value corresponding to the Konishi operator. Our results indicate that the related calculations and conclusions of Gromov, Kazakov and Vieira should be interpreted with caution. The phenomenon we discuss might potentially explain the mismatch between their recent computation of the scaling dimension of the Konishi operator and the one done by Roiban and Tseytlin by using the string theory sigma model.

hep-th↗

arXiv2010

Five-loop Konishi from the Mirror TBA

We use the Thermodynamic Bethe Ansatz equations for the AdS_5 \times S^5 mirror model to derive the five-loop anomalous dimension of the Konishi operator. We show numerically that the corresponding result perfectly agrees with the one recently obtained via the generalized Luscher formulae. This constitutes an important test of the AdS/CFT TBA system.

hep-th↗

arXiv2009

Bound State Transfer Matrix for AdS5 x S5 Superstring

We apply the algebraic Bethe ansatz technique to compute the eigenvalues of the transfer matrix constructed from the general bound state S-matrix of the light-cone AdS5 x S5 superstring. This allows us to verify certain conjectures on the quantum characteristic function, and to extend them to the general case.

hep-th↗

arXiv2009

Temperature quantization from the TBA equations

We analyze the Thermodynamic Bethe Ansatz equations for the mirror model which determine the ground state energy of the light-cone AdS_5 x S^5 superstring living on a cylinder. The light-cone momentum of string is equal to the circumference of the cylinder, and is identified with the inverse temperature of the mirror model. We show that the natural requirement of the analyticity of the Y-functions leads to the quantization of the temperature of the mirror model which has never been observed in any other models.

hep-th↗

arXiv2009

Giant Magnons on CP^3 by Dressing Method

We consider classical string spectrum of R x CP^3, and construct a family of solutions with residual SU(2) symmetry by the dressing method on SU(4)/U(3) sigma model. All of them obey the square-root type dispersion relation, as is expected from the su(2|2) symmetry. A single dyonic giant magnon is not found in this approach.

hep-th↗

arXiv2009

Spin-state transition and phase separation in multi-orbital Hubbard model

We study spin-state transition and phase separation involving this transition based on the milti-orbital Hubbard model. Multiple spin states are realized by changing the energy separation between the two orbitals and the on-site Hund coupling. By utilizing the variational Monte-Carlo simulation, we analyze the electronic and magnetic structures in hole doped and undoped states. Electronic phase separation occurs between the low-spin band insulating state and the high-spin ferromagnetic metallic one. Difference of the band widths in the two orbitals is of prime importance for the spin-state transition and the phase separation.

cond-mat.str-el↗

arXiv2008

Finite-Size Effects for Dyonic Giant Magnons

We compute finite-size corrections to dyonic giant magnons in two ways. One is by examining the asymptotic behavior of helical strings of hep-th/0609026 as elliptic modulus k goes to unity, and the other is by applying the generalized Luscher formula for mu-term of arXiv:0708.2208 to the situation in which incoming particles are boundstates. By careful choice of poles in the su(2|2)^2-invariant S-matrix, we find agreement of the two results, which makes possible to predict the (leading) finite-size correction for dyonic giant magnons to all orders in the 't Hooft coupling.

hep-th↗

arXiv2008

Finite-Size Effects for Multi-Magnon States

We propose the generalized Luscher formula for multi-magnon states by which one can compute the finite-size correction to the energy of multi giant magnons at classical and one-loop levels. It is shown that the F-term of our formula is consistent with the exact finite-size spectrum of the sinh-Gordon model, and the mu-term agrees with the finite-size energy of magnon boundstate of the asymptotic Bethe Ansatz in the su(2) sector at strong coupling. In an appendix, we evaluate our formula at weak coupling under some approximations, and find that the transcendental terms arise from a sum over an infinite tower of BPS boundstates.

hep-th↗

arXiv2007

Large Winding Sector of AdS/CFT

We study a family of classical strings on R x S^3 subspace of the AdS_5 x S^5 background that interpolates between pulsating strings and single-spike strings. They are obtained from the helical strings of hep-th/0609026 by interchanging worldsheet time and space coordinates, which maps rotating/spinning string states with large spins to oscillating states with large winding numbers. From a finite-gap perspective, this transformation is realised as an interchange of quasi-momentum and quasi-energy defined for the algebraic curve. The gauge theory duals are also discussed, and are identified with operators in the non-holomorphic sector of N=4 super Yang-Mills. They can be viewed as excited states above the ``antiferromagnetic'' state, which is ``the farthest from BPS'' in the spin-chain spectrum. Furthermore, we investigate helical strings on AdS_3 x S^1 in an appendix.

hep-th↗

arXiv2007

A Perspective on Classical Strings from Complex Sine-Gordon Solitons

We study a family of classical string solutions with large spins on R x S^3 subspace of AdS_5 x S^5 background, which are related to Complex sine-Gordon solitons via Pohlmeyer's reduction. The equations of motion for the classical strings are cast into Lame equations and Complex sine-Gordon equations. We solve them under periodic boundary conditions, and obtain analytic profiles for the closed strings. They interpolate two kinds of known rigid configurations with two spins: on one hand, they reduce to folded or circular spinning/rotating strings in the limit where a soliton velocity goes to zero, while on the other hand, the dyonic giant magnons are reproduced in the limit where the period of a kink-array goes to infinity.

hep-th↗

arXiv2006

More anomaly-free models of six-dimensional gauged supergravity

We construct a huge number of anomaly-free models of six-dimensional N = (1,0) gauged supergravity. The gauge groups are products of U(1) and SU(2), and every hyperino is charged under some of the gauge groups. It is also found that the potential may have flat directions when the R-symmetry is diagonally gauged together with another gauge group. In an appendix, we determine the contribution to the global SU(2) anomaly from symplectic Majorana Weyl fermions in six dimensions.

hep-th↗