Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Physics A Mathematical and Theoretical

Perfect state transfer in inhomogeneous XX model of q -Racah type

Nicolas Crampé, S. Lafrance, Charles Robillard, Luc Vinet

Published May 22, 2026• 0 citations
Publisher

Abstract

Abstract New exactly solvable one-dimensional XX spin chain models that exhibit perfect state transfer (PST) are defined. These models have inhomogeneous couplings and magnetic fields determined from the three-term recurrence relations satisfied by the q -Racah and para q -Racah polynomials. Due to this connection with orthogonal polynomials, the one-excitation sector can be solved analytically. This allows us to provide explicit sets of conditions on the polynomial parameters that guarantee the occurrence of PST across these spin chains.

DOI
10.1088/1751-8121/ae7223

Related papers

Perfect state transfer in inhomogeneous XX model of q-Racah type

Nicolas Crampé, Lafrance, Simon, Charles Robillard +1 more

New exactly solvable one-dimensional XX spin chain models that exhibit perfect state transfer are defined. These models have inhomogeneous couplings and magnetic fields determined from the three-term recurrence relations satisfied by the q-Racah and para q-Racah polynomials. Due to this connection with orthogonal polynomials, the one-excitation sector can be solved analytically. This allows us to provide explicit sets of conditions on the polynomial parameters that guarantee the occurrence of perfect state transfer across these spin chains.

arXiv:2512.12419•Dec 13, 2025•0 citations

An analytic spin chain model with fractional revival

Jean-Michel Lemay, Luc Vinet, Alexei S. Zhedanov

Abstract New analytic spin chains with fractional revival are introduced. Their nearest-neighbor couplings and local magnetic fields correspond to the recurrence coefficients of para-Racah polynomials which are orthogonal on quadratic bi-lattices. These models generalize the spin chain associated to the dual-Hahn polynomials. Instances where perfect state transfer also occurs are identified.

arXiv:1509.08965•Journal of Physics A Mathematical and Theoretical•Jul 8, 2016•16 citations

How to construct spin chains with perfect state transfer

Luc Vinet, Alexei S. Zhedanov

A method to systematically construct the $XX$ quantum spin chains with nearest-neighbor interactions that allow perfect state transfer (PST) is shown. Sets of orthogonal polynomials (OPs) are in correspondence with such systems. The key observation is that for any admissible one-excitation energy spectrum, the weight function of the associated OPs is uniquely prescribed. This entails the complete characterization of these PST models with the mirror-symmetry property arising as a corollary. A simple and efficient algorithm to obtain the corresponding Hamiltonians is presented. A model connected to a special case of the symmetric $q$-Racah polynomials is offered. An explanation of how additional models with PST can be derived from a parent system by removing energy levels from the one-excitation spectrum of the latter is given. This is achieved through Christoffel transformations and is also completely constructive in regards to the Hamiltonians.

arXiv:1110.6474•Physical Review A•Jan 23, 2012•92 citations

Quantum state transfer in spin chains withq-deformed interaction terms

E. I. Jafarov, Joris Van Der Jeugt

We study the time evolution of a single spin excitation state in certain linear spin chains, as a model for quantum communication. Some years ago it was discovered that when the spin chain data (the nearest neighbour interaction strengths and the magnetic field strengths) are related to the Jacobi matrix entries of Krawtchouk polynomials or dual Hahn polynomials, so-called perfect state transfer takes place. The extension of these ideas to other types of discrete orthogonal polynomials did not lead to new models with perfect state transfer, but did allow more insight in the general computation of the correlation function. In the present paper, we extend the study to discrete orthogonal polynomials of q-hypergeometric type. A remarkable result is a new analytic model where perfect state transfer is achieved: this is when the spin chain data are related to the Jacobi matrix of q-Krawtchouk polynomials. The other cases studied here (affine q-Krawtchouk polynomials, quantum q-Krawtchouk polynomials, dual q-Krawtchouk polynomials, q-Hahn polynomials, dual q-Hahn polynomials and q-Racah polynomials) do not give rise to models with perfect state transfer. However, the computation of the correlation function itself is quite interesting, leading to advanced q-series manipulations.

arXiv:1005.2912•Journal of Physics A Mathematical and Theoretical•Sep 3, 2010•19 citations

Dual -1 Hahn polynomials and perfect state transfer

Luc Vinet, Alexei S. Zhedanov

We find all the XX spin chains with perfect state transfer (PST) that are connected with the dual -1 Hahn polynomials R n ( x ; α , β , N ). For N odd we recover a model that had already been identified while for N even, we obtain a new system exhibiting PST.

arXiv:1110.6477•Journal of Physics Conference Series•Feb 8, 2012•15 citations

Perfect state transfer in a spin chain without mirror symmetry

Gabriel Coutinho, Luc Vinet, Hanmeng Zhan +1 more

Abstract We introduce an analytical XX spin chain with asymmetrical transport properties. It has an even number N + 1 of sites labeled by . It does not exhibit perfect state transfer (PST) from end-to-end but rather from the first site to the next to last one. In fact, PST of one-excitation states takes place between the even sites: , ; while states localized at a single odd site undergo fractional revival (FR) over odd sites only. Perfect return is witnessed at double the PST/FR time. The couplings and local magnetic fields are related to the recurrence coefficients of the dual −1 Hahn polynomials.

arXiv:1903.04707•Journal of Physics A Mathematical and Theoretical•Sep 24, 2019•4 citations
Abstract New exactly solvable one-dimensional XX spin chain models that exhibit perfect state transfer (PST) are defined. These models have inhomogeneous couplings and magnetic fields determined from the three-term recurrence relations satisfied by the q -Racah and para q -Racah polynomials. Due to this connection with orthogonal polynomials, the one-excitation sector can be solved analytically. This allows us to provide explicit sets of conditions on the polynomial parameters that guarantee the occurrence of PST across these spin chains.
New exactly solvable one-dimensional XX spin chain models that exhibit perfect state transfer are defined. These models have inhomogeneous couplings and magnetic fields determined from the three-term recurrence relations satisfied by the q-Racah and para q-Racah polynomials. Due to this connection with orthogonal polynomials, the one-excitation sector can be solved analytically. This allows us to provide explicit sets of conditions on the polynomial parameters that guarantee the occurrence of perfect state transfer across these spin chains.
A method to systematically construct the XXXXXX quantum spin chains with nearest-neighbor interactions that allow perfect state transfer (PST) is shown. Sets of orthogonal polynomials (OPs) are in correspondence with such systems. The key observation is that for any admissible one-excitation energy spectrum, the weight function of the associated OPs is uniquely prescribed. This entails the complete characterization of these PST models with the mirror-symmetry property arising as a corollary. A simple and efficient algorithm to obtain the corresponding Hamiltonians is presented. A model connected to a special case of the symmetric qqq-Racah polynomials is offered. An explanation of how additional models with PST can be derived from a parent system by removing energy levels from the one-excitation spectrum of the latter is given. This is achieved through Christoffel transformations and is also completely constructive in regards to the Hamiltonians.
We study the time evolution of a single spin excitation state in certain linear spin chains, as a model for quantum communication. Some years ago it was discovered that when the spin chain data (the nearest neighbour interaction strengths and the magnetic field strengths) are related to the Jacobi matrix entries of Krawtchouk polynomials or dual Hahn polynomials, so-called perfect state transfer takes place. The extension of these ideas to other types of discrete orthogonal polynomials did not lead to new models with perfect state transfer, but did allow more insight in the general computation of the correlation function. In the present paper, we extend the study to discrete orthogonal polynomials of q-hypergeometric type. A remarkable result is a new analytic model where perfect state transfer is achieved: this is when the spin chain data are related to the Jacobi matrix of q-Krawtchouk polynomials. The other cases studied here (affine q-Krawtchouk polynomials, quantum q-Krawtchouk polynomials, dual q-Krawtchouk polynomials, q-Hahn polynomials, dual q-Hahn polynomials and q-Racah polynomials) do not give rise to models with perfect state transfer. However, the computation of the correlation function itself is quite interesting, leading to advanced q-series manipulations.
Abstract We introduce an analytical XX spin chain with asymmetrical transport properties. It has an even number N + 1 of sites labeled by . It does not exhibit perfect state transfer (PST) from end-to-end but rather from the first site to the next to last one. In fact, PST of one-excitation states takes place between the even sites: , ; while states localized at a single odd site undergo fractional revival (FR) over odd sites only. Perfect return is witnessed at double the PST/FR time. The couplings and local magnetic fields are related to the recurrence coefficients of the dual −1 Hahn polynomials.