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Jun'ichi Shiraishi

Publications and source records attributed to Jun'ichi Shiraishi.

At least 37 records · Page 2Linked to original sources
arXiv2012

A direct approach to the bispectral problem for the Ruijsenaars-Macdonald q-difference operators

We present a direct approach to the bispectral problem associated with the Ruijsenaars-Macdonald q-difference operators of GL type. We give an explicit construction of the meromorphic function psi_n(x;s|q,t) on T^n_x T^n_s, which is the solution of the bispectral problem up to a certain gauge transformation. Some basic properties of psi_n(x;s|q,t) are studied, including the structure of the divisor of poles, the symmetries psi_n(x;s|q,t)=psi_n(s;x|q,t)=psi_n(x;s|q,q/t), and the recursive structure described in terms of Jackson integrals or q-difference operators.

math.QA↗
arXiv2010

Periodic Benjamin-Ono equation with discrete Laplacian and 2D-Toda Hierarchy

We study the relation between the periodic Benjamin-Ono equation with discrete Laplacian and the two dimensional Toda hierarchy. We introduce the tau-functions tau_pm(z) for the periodic Benjamin-Ono equation, construct two families of integrals of motion {M_1,M_2,cdots}, {overline{M}_1,overline{M}_2,cdots}, and calculate some examples of the bilinear equations using the Hamiltonian structure. We confirmed that some of the low lying bilinear equations agree with the ones obtained from a certain reduction of the 2D Toda hierarchy.

math-ph↗
arXiv2009

On some special solutions to periodic Benjamin-Ono equation with discrete Laplacian

We investigate a periodic version of the Benjamin-Ono (BO) equation associated with a discrete Laplacian. We find some special solutions to this equation, and calculate the values of the first two integrals of motion $I_1$ and $I_2$ corresponding to these solutions. It is found that there exists a strong resemblance between them and the spectra for the Macdonald $q$-difference operators. To better understand the connection between these classical and quantum integrable systems, we consider the special degenerate case corresponding to $q=0$ in more detail. Namely, we give general solutions to this degenerate periodic BO, obtain explicit formulas representing all the integrals of motions $I_n$ ($n=1,2,...$), and successfully identify it with the eigenvalues of Macdonald operators in the limit $q\to 0$, i.e. the limit where Macdonald polynomials tend to the Hall-Littlewood polynomials.

nlin.SI↗
arXiv2009

Mutual Information and Boson Radius in c=1 Critical Systems in One Dimension

We study the generic scaling properties of the mutual information between two disjoint intervals, in a class of one-dimensional quantum critical systems described by the c=1 bosonic field theory. A numerical analysis of a spin-chain model reveals that the mutual information is scale-invariant and depends directly on the boson radius. We interpret the results in terms of correlation functions of branch-point twist fields. The present study provides a new way to determine the boson radius, and furthermore demonstrates the power of the mutual information to extract more refined information of conformal field theory than the central charge.

cond-mat.stat-mech↗
arXiv2005

A Commutative Family of Integral Transformations and Basic Hypergeometric Series. II. Eigenfunctions and Quasi-Eigenfunctions

A series of conjectures is obtained as further investigation of the integral transformation I(alpha) introduced in the previous paper. A Macdonald-type difference operator D is introduced. It is conjectured that D and I(alpha) are commutative with each other. Studying the series for the eigenfunctions under termination conditions, it is observed that a deformed Weyl group action appears as a hidden symmetry. An infinite product formula for the eigenfunction is found for a spacial case of parameters. A one parameter family of hypergeometric-type series F(alpha) is introduced. The series F(alpha) is caracterized by a covariant transformation property I(alpha q^{-1} t) F(alpha)=F(alpha q^{-1} t) and a certain initial condition given at alpha=t^{1/2}. We call F(alpha) the `quasi-eigenfunction' for short. A class of infinite product-type expressions are conjectured for F(alpha) at the special points alpha=-t^{1/2}, alpha=q, alpha=pm q^{1/2}t^{1/2}, and alpha=pm q^{ell}t^{1/2} (ell=1,2,3,cdots).

math.QA↗
arXiv2005

A Conjecture about Raising Operators for Macdonald Polynomials

A multivariable hypergeometric-type formula for raising operators of the Macdonald polynomials is conjectured. It is proved that this agrees with Jing and Jozefiak's expression for the two-row Macdonald polynomials, and also with Lassalle and Schlosser's formula for partitions with length three.

math.QA↗
arXiv2005

A Commutative Family of Integral Transformations and Basic Hypergeometric Series. I. Eigenfunctions

It is conjectured that a class of n-fold integral transformations {I(alpha)|alpha in {C}} forms a mutually commutative family, namely, we have I(alpha) I(beta)=I(beta) I(alpha) for all alpha, beta in {C}. The commutativity of I(alpha) for the two-fold integral case is proved by using several summation and transformation formulas for the basic hypergeometric series. An explicit formula for the complete system of the eigenfunctions for n=3 is conjectured. In this formula and in a partial result for n=4, it is observed that all the eigenfunctions do not depend on the spectral parameter alpha of I(alpha).

math.QA↗
arXiv2004

Correspondence between conformal field theory and Calogero-Sutherland model

We use the Jack symmetric functions as a basis of the Fock space, and study the action of the Virasoro generators $L_n$. We calculate explicitly the matrix elements of $L_n$ with respect to the Jack-basis. A combinatorial procedure which produces these matrix elements is conjectured. As a limiting case of the formula, we obtain a Pieri-type formula which represents a product of a power sum and a Jack symmetric function as a sum of Jack symmetric functions. Also, a similar expansion was found for the case when we differentiate the Jack symmetric functions with respect to power sums. As an application of our Jack-basis representation, a new diagrammatic interpretation is presented, why the singular vectors of the Virasoro algebra are proportional to the Jack symmetric functions with rectangular diagrams. We also propose a natural normalization of the singular vectors in the Verma module, and determine the coefficients which appear after bosonization in front of the Jack symmetric functions.

hep-th↗
arXiv2003

Free field constructions for the elliptic algebra ${\cal A}_{q,p}(\hat{sl}_2)$ and Baxter's eight-vertex model

Three examples of free field constructions for the vertex operators of the elliptic quantum group ${\cal A}_{q,p}(\hat{sl}_2)$ are obtained. Two of these (for $p^{1/2}=\pm q^{3/2},p^{1/2}=-q^2$) are based on representation theories of the deformed Virasoro algebra, which correspond to the level 4 and level 2 $Z$-algebra of Lepowsky and Wilson. The third one ($p^{1/2}=q^{3}$) is constructed over a tensor product of a bosonic and a fermionic Fock spaces. The algebraic structure at $p^{1/2}=q^{3}$, however, is not related to the deformed Virasoro algebra. Using these free field constructions, an integral formula for the correlation functions of Baxter's eight-vertex model is obtained. This formula shows different structure compared with the one obtained by Lashkevich and Pugai.

math.QA↗
arXiv1998

Novel vortex lattice transition in d-wave superconductors

We study the vortex state in a magnetic field parallel to the $c$ axis in the framework of the extended Ginzburg Landau equation. We find the vortex acquires a fourfold modulation proportional to $\cos(4ϕ)$ where $ϕ$ is the angle ${\bf r}$ makes with the $a$-axis. This term gives rise to an attractive interaction between two vortices when they are aligned parallel to $(1,1,0)$ or $(1,-1,0)$. We predict the first order vortex lattice transition at $B=H_{cr}\sim κ^{-1} H_{c2}(t)$ from triangular into the square lattice tilted by $45^\circ$ from the $a$ axis. This gives the critical field $H_{cr}$ a few Tesla for YBCO and Bi2212 monocrystals at low temperatures ($T\leq 10 K$).

cond-mat.supr-con↗
arXiv1998

A coset-type construction for the deformed Virasoro algebra

An analog of the minimal unitary series representations for the deformed Virasoro algebra is constructed using vertex operators of the quantum affine algebra $U_q(\hat{sl}_2)$. A similar construction is proposed for the elliptic algebra $A_{q,p}(\hat{sl}_2)$.

q-alg↗
arXiv1997

Vortex lattice transition in D-wave superconductors

Making use of the extended Ginzburg Landau theory, which includes the fourth order derivative term, we study the vortex state in a magnetic field parallel to the $ c$ axis. The vortex core structure is distorted due to this higher order term, which reveals t he fourfold symmetry. Futher, this distortion gives rise to the core interaction energy, which favo rs a square lattice tilted by $45^\circ$ from the $a$ axis. The critical field of this transition is determined. The magnetization diverges at the transition. This suggests the transition is of the fi rst order.

cond-mat↗
arXiv1996

Current and charge distributions of the fractional quantum Hall liquids with edges

An effective Chern-Simons theory for the quantum Hall states with edges is studied by treating the edge and bulk properties in a unified fashion. An exact steady-state solution is obtained for a half-plane geometry using the Wiener-Hopf method. For a Hall bar with finite width, it is proved that the charge and current distributions do not have a diverging singularity. It is shown that there exists only a single mode even for the hierarchical states, and the mode is not localized exponentially near the edges. Thus this result differs from the edge picture in which electrons are treated as strictly one dimensional chiral Luttinger liquids.

cond-mat↗
arXiv1995

A Quantum Deformation of the Virasoro Algebra and the Macdonald Symmetric Functions

A quantum deformation of the Virasoro algebra is defined. The Kac determinants at arbitrary levels are conjectured. We construct a bosonic realization of the quantum deformed Virasoro algebra. Singular vectors are expressed by the Macdonald symmetric functions. This is proved by constructing screening currents acting on the bosonic Fock space.

q-alg↗
arXiv1992

The Non-perturbative Canonical Quantization of the N=1 Supergravity

The non-perturbative canonical quantization of the N=1 supergravity with the non-zero cosmological constant is studied using the Ashtekar formalism. A semi-classical wave function is obtained and it has the form of the exponential of the N=1 supersymmetric extension of the Chern-Simons functional. The N=1 supergravity in the Robertson-Walker universe is also examined and some analytic solutions are obtained. (We omit all graphs in the following LaTex file.)

hep-th↗