Exotic quantum holonomy in Hamiltonian systems (2009)
Cheon, Taksu, Tanaka, Atushi, Kim, Sang Wook
We study the evolution of quantum eigenstates in the presence of level crossing under adiabatic cyclic change of environmental parameters. We find that exotic holonomies, indicated by exchange of the...
Spectral filtering in quantum Y-junction (2009)
Cheon, Taksu, Exner, Pavel, Turek, Ondrej
We examine scattering properties of singular vertex of degree $n=2$ and $n=3$, taking advantage of a new form of representing the vertex boundary condition, which has been devised to approximate a...
Approximation of a general singular vertex coupling in quantum graphs (2009)
Cheon, Taksu, Exner, Pavel, Turek, Ondrej
The longstanding open problem of approximating all singular vertex couplings in a quantum graph is solved. We present a construction in which the edges are decoupled; an each pair of their endpoints...
Exotic quantum holonomy induced by degeneracy hidden in complex parameter space (2009)
Kim, Sang Wook, Cheon, Taksu, Tanaka, Atushi
An adiabatic change of a bound state along a closed circuit in the parameter space can induces holonomies not only in the phase of the state, but also in the associated eigenspace and eigenvalue. The...
A Unified Theory of Quantum Holonomies (2009)
A periodic change of slow environmental parameters of a quantum system induces quantum holonomy. The phase holonomy is a well-known example. Another is a more exotic kind that exhibits eigenvalue and...
New anatomy of quantum holonomy (2008)
We present a unified formulation of quantum holonomy which is capable of describing all of its known varieties. The full role of non-Abelian gauge connection is elucidated. As examples, solvable...
Iqbal, Azhar, Cheon, Taksu, Abbott, Derek
This paper extends our probabilistic framework for two-player quantum games to the mutliplayer case, while giving a unified perspective for both classical and quantum games. Considering joint...
Tsubasa Ichikawa, Izumi Tsutsui, Taksu Cheon
We present a novel formulation of quantum game theory based on the Schmidt decomposition, which has the merit that the entanglement of quantum strategies is manifestly quantified. We apply this...
Iqbal, Azhar, Cheon, Taksu, Abbott, Derek Zarir
Copyright © 2008 Elsevier B.V. All rights reserved.
Iqbal, Azhar, Cheon, Taksu, Abbott, Derek Zarir
Copyright © 2008 Elsevier B.V. All rights reserved.
Constructing multi-player quantum games from non-factorizable joint probabilities (2007)
We use the standard three-party Einstein-Podolsky-Rosen (EPR) setting in order to play general three-player non-cooperative symmetric games. We analyze how the peculiar non-factorizable joint...
In their Letter [A. Tanaka and M. Miyamoto, Phys. Rev. Lett. 98, 160407 (2007)], Tanaka and Miyamoto introduce a kicked spin model, for which they point out the generic existence of exotic eigenvalue...
Bayesian Nash Equilibria and Bell Inequalities (2007)
Games with incomplete information are formulated in a multi-sector probability matrix formalism that can cope with quantum as well as classical strategies. An analysis of classical and quantum...
Anomalous Relativistic Tunneling and Exotic Point Interactions (2007)
We examine one-dimensional quantum scattering of a Dirac particle off relativistic potential barriers. With proper considerations of Dirac sea, existence of anomalous tunneling at zero...
Constructing quantum games from non-factorizable joint probabilities (2007)
A probabilistic framework is developed that gives a unifying perspective on both the classical and the quantum games. We suggest exploiting peculiar probabilities involved in Einstein-Podolsky-Rosen...
Evolutionary stability in quantum games (2007)
In evolutionary game theory an Evolutionarily Stable Strategy (ESS) is a refinement of the Nash equilibrium concept that is sometimes also recognized as evolutionary stability. It is a game-theoretic...
Quantum Game Theory Based on the Schmidt Decomposition: Can Entanglement Resolve Dilemmas? (2007)
Ichikawa, Tsubasa, Tsutsui, Izumi, Cheon, Taksu
We present a novel formulation of quantum game theory based on the Schmidt decomposition, which has the merit that the entanglement of quantum strategies is manifestly quantified. We apply this...
Irregular dynamics in a solvable one-dimensional quantum graph (2006)
We show that the quantum single particle motion on a one-dimensional line with Fülöp–Tsutsui point interactions exhibits characteristics usually associated with nonintegrable systems both in...
Game Theory Formulated on Hilbert Space (2006)
We present a consistent formulation of quantum game theory that accommodates all possible strategies in Hilbert space. The physical content of the quantum strategy is revealed as a family of...
Irregular Dynamics in a Solvable One-Dimensional Quantum Graph (2005)
We show that the quantum single particle motion on a one-dimensional line with Fulop-Tsutsui point interactions exhibits characteristics usually associated with nonintegrable systems both in bound...
Metastable Congested States in Multisegment Traffic Cellular Automaton (2005)
Nishimura, Yutaka, Cheon, Taksu, Seba, Petr
We investigate a simple multisegment cellular automaton model of traffic flow. With the introduction of segment-dependent deceleration probability, metastable congested states in the intermediate...
Classical and Quantum Contents of Solvable Game Theory on Hilbert Space (2005)
A simple and general formulation of the quantum game theory is presented, accommodating all possible strategies in the Hilbert space for the first time. The theory is solvable for the two strategy...
Altruistic Contents of Quantum Prisoner's Dilemma (2004)
We examine the classical contents of quantum games. It is shown that a quantum strategy can be interpreted as a classical strategies with effective density-dependent game matrices composed of...
An approximation to $\delta'$ couplings on graphs (2004)
We discuss a general parametrization for vertices of quantum graphs and show, in particular, how the $\delta'_s$ and $\delta'$ coupling at an $n$ edge vertex can be approximated by means of $n+1$...
Locational Qubit Realization with One-dimensional Contact Interactions (2004)
We show that the U(2) group structure of thin barriers can be adopted for quantum information processing when used in combination with environmental potential whose bouncing modes are profile...
Cheon, Taksu, Tsutsui, Izumi, Fulop, Tamas
We show that the U(2) family of point interactions on a line can be utilized to provide the U(2) family of qubit operations for quantum information processing. Qubits are realized as localized states...
Suppression of Ecological Competition by Apex Predator (2003)
In the framework of Lotka-Volterra dynamics with evolutionary parameter variation, it is shown that a system of two competing species which is evolutionarily unstable, if left to themselves, is...
Spectral properties on a circle with a singularity (2003)
Fulop, Tamas, Tsutsui, Izumi, Cheon, Taksu
We investigate the spectral and symmetry properties of a quantum particle moving on a circle with a pointlike singularity (or point interaction). We find that, within the U(2) family of the quantum...
Altruistic Duality in Evolutionary Game Theory (2003)
A game-theoretic model of social preference and enlightened self-interest is formulated. Existence of symmetry and duality in the game matrices with altruistic social preference is revealed. The...
Evolutionary Stability of Ecological Hierarchy (2003)
A self-similar hierarchical solution that is both dynamically and evolutionarily stable is found to the multi dimensional Lotka-Volterra equation with a single chain of prey-predator relations. This...
Connection Conditions and the Spectral Family under Singular Potentials (2002)
Tsutsui, Izumi, Fulop, Tamas, Cheon, Taksu
To describe a quantum system whose potential is divergent at one point, one must provide proper connection conditions for the wave functions at the singularity. Generalizing the scheme used for point...
Extended Standard Map with Spatio-Temporal Asymmetry (2002)
Cheon, Taksu, Exner, Pavel, Seba, Petr
We analyze the transport properties of a set of symmetry-breaking extensions %, both spatial and temporal, of the Chirikov--Taylor Map. The spatial and temporal asymmetries result in the loss of...
Quantum contact interactions (2002)
The existence of several exotic phenomena, such as duality and spectral anholonomy is pointed out in one-dimensional quantum wire with a single defect. The topological structure in the spectral space...
Persistent currents due to point obstacles (2002)
We discuss properties of the two-dimensional Landau Hamiltonian perturbed by a family of identical $\delta$ potentials arranged equidistantly along a closed loop. It is demonstrated that for the loop...
Classical Aspects of Quantum Walls in One Dimension (2001)
Fulop, Tamas, Cheon, Taksu, Tsutsui, Izumi
We investigate the system of a particle moving on a half line x >= 0 under the general walls at x = 0 that are permitted quantum mechanically. These quantum walls, characterized by a parameter L, are...
Spectral Structure of Quantum Line with a Defect (2001)
Cheon, Taksu, Fulop, Tamas, Tsutsui, Izumi
We study the spectral properties of one-dimensional quantum wire with a single defect. We reveal the existence of the non-trivial topological structures in the spectral space of the system, which are...
Moebius Structure of the Spectral Space of Schroedinger Operators with Point Interaction (2001)
Tsutsui, Izumi, Fulop, Tamas, Cheon, Taksu
The Schroedinger operator with point interaction in one dimension has a U(2) family of self-adjoint extensions. We study the spectrum of the operator and show that (i) the spectrum is uniquely...
Symmetry, Duality and Anholonomy of Point Interactions in One Dimension (2000)
Cheon, Taksu, Fulop, Tamas, Tsutsui, Izumi
We analyze the spectral structure of the one dimensional quantum mechanical system with point interaction, which is known to be parametrized by the group U(2). Based on the classification of the...
Wave Function Shredding by Sparse Quantum Barriers (2000)
Cheon, Taksu, Exner, Pavel, Seba, Petr
We discuss a model in which a quantum particle passes through $\delta$ potentials arranged in an increasingly sparse way. For infinitely many barriers we derive conditions, expressed in terms ergodic...
Duality and Anholonomy in Quantum Mechanics of 1D Contact Interactions (2000)
Tsutsui, Izumi, Fulop, Tamas, Cheon, Taksu
We study systems with parity invariant contact interactions in one dimension. The model analyzed is the simplest nontrivial one --- a quantum wire with a point defect --- and yet is shown to exhibit...
Continuous Spectra of Generalized Kronig-Penney Model (1999)
The standard Kronig-Penney model with periodic $\delta$ potentials is extended to the cases with generalized contact interactions. The eigen equation which determines the dispersion relation for...
Shigehara, T., Mizoguchi, H., Mishima, T., Cheon, Taksu
We first give the solution for the local approximation of a four parameter family of generalized one-dimensional point interactions within the framework of non-relativistic model with three...
Shigehara, T., Mizoguchi, H., Mishima, T., Cheon, Taksu
We propose a new method to construct a four parameter family of quantum-mechanical point interactions in one dimension, which is known as all possible self-adjoint extensions of the symmetric...
Cheon, Taksu, Shigehara, T., Takayanagi, K.
We prove that the separable and local approximations of the discontinuity-inducing zero-range interaction in one-dimensional quantum mechanics are equivalent. We further show that the interaction...
Some Aspects of Generalized Contact Interaction in One-Dimensional Quantum Mechanics (1998)
We construct a one-dimensional contact interaction ($\epsilon$ potential) which induces the discontinuity of the wave function while keeping its derivative continuous. By combining the $\epsilon$...
Shigehara, T., Yokoyama, M., Mizoguchi, H., Mishima, T., Cheon, Taksu
In order to give some insight into a role of small impurities on the electron motion in microscopic devices, we examine from a general viewpoint, the effect of small obstacles on a particle motion at...
For a system of spinless one-dimensional fermions, the non-vanishing short-range limit of two-body interaction is shown to induce the wave-function discontinuity. We prove the equivalence of this...
We analyze the eigenvalue problem of a quantum particle on the line with the generalized pointlike potential of three parameter family. It is shown that the energy surface in the parameter space has...
Chaos Induced by Quantization (1998)
Shigehara, Takaomi, Mizoguchi, Hiroshi, Mishima, Taketoshi, Cheon, Taksu
In this paper, we show that two-dimensional billiards with point interactions inside exhibit a chaotic nature in the microscopic world, although their classical counterpart is non-chaotic. After...
Shigehara, T., Mizoguchi, H., Mishima, T., Cheon, Taksu
We discuss spectral properties of the Laplacian with multiple ($N$) point interactions in two-dimensional bounded regions. A mathematically sound formulation for the problem is given within the...
Wave Chaos in Quantum Pseudointegrable Billiards (1997)
Shigehara, T., Mizoguchi, H., Mishima, T., Cheon, Taksu
We clarify from a general perspective, the condition for the appearance of chaotic energy spectrum in quantum pseudointegrable billiards with a point scatterer inside.
Realizing Discontinuous Wave Functions with Renormalized Short-Range Potentials (1997)
It is shown that a potential consisting of three Dirac's delta functions on the line with disappearing distances can give rise to the discontinuity in wave functions with the proper renormalization...
Spectral Properties of Three-Dimensional Quantum Billiards with a Pointlike Scatterer (1997)
We examine the spectral properties of three-dimensional quantum billiards with a single pointlike scatterer inside. It is found that the spectrum shows chaotic (random-matrix-like) characteristics...
Resonance Tunneling in Double-Well Billiards with a Pointlike Scatterer (1996)
The coherent tunneling phenomenon is investigated in rectangular billiards divided into two domains by a classically unclimbable potential barrier. We show that by placing a pointlike scatterer...
Flux String in Quantum Billiards with Two Particles (1996)
We examine the quantum motion of two particles interacting through a contact force which are confined in a rectangular domain in two and three dimensions. When there is a difference in the mass scale...
Wave Chaos in Quantum Billiards with Small but Finite-Size Scatterer (1996)
We study the low energy quantum spectra of two-dimensional rectangular billiards with a small but finite-size scatterer inside. We start by examining the spectral properties of billiards with a...
Green Function Monte Carlo Method for Excited States of Quantum System (1996)
A novel scheme to solve the quantum eigenvalue problem through the imaginary-time Green function Monte Carlo method is presented. This method is applicable to the excited states as well as to the...
Level spacing distribution of pseudointegrable billiard (1995)
Shigehara, T., Yoshinaga, N., Cheon, Taksu, Mizusaki, T.
In this paper, we examine the level spacing distribution $P(S)$ of the rectangular billiard with a single point-like scatterer, which is known as pseudointegrable. It is shown that the observed...
Nuclear Mass Dependence of Chaotic Dynamics in Ginocchio Model (1995)
Yoshinaga, Naotaka, Yoshida, Nobuaki, Shigehara, Takaomi, Cheon, Taksu
The chaotic dynamics in nuclear collective motion is studied in the framework of a schematic shell model which has only monopole and quadrupole degrees of freedom. The model is shown to reproduce the...
Response Function of Asymmetric Nuclear Matter (1995)
Takayanagi, Kazuo, Cheon, Taksu
The charge longitudinal response function is examined in the framework of the random-phase approximation in an isospin-asymmetric nuclear matter where proton and neutron densities are different. This...
Folded Bifurcation in Coupled Asymmetric Logistic Maps (1995)
Midorikawa, Shoichi, Kubo, Takayuki, Cheon, Taksu
A system of coupled two logistic maps, one periodic and the other chaotic, is studied. It is found that with the variation of the coupling strength, the system displays several curious features such...
Isospin dependent effective interaction in nucleon-nucleus scattering (1995)
Cheon, Taksu, Takayanagi, Kazuo
The isospin-dependent component of the effective nucleon-nucleon interaction that causes the $\Delta T=1$ (p, p') and (p, n) reactions off nuclei is studied. It is shown that the corrections to the...
Classical and Quantal Irregular Scatterings with Complex Target (1995)
One-dimensional scattering by a target with two internal degrees of freedom is investigated. The damping of resonance peaks and the associated appearance of the fluctuating background in the quantum...
Scale Anomaly and Quantum Chaos in the Billiards with Pointlike Scatterers (1995)
Cheon, Taksu, Shigehara, Takaomi
We argue that the random-matrix like energy spectra found in pseudointegrable billiards with pointlike scatterers are related to the quantum violation of scale invariance of classical analogue...
Geometric Phase in Quantum Billiards with a Pointlike Scatterer (1995)
Cheon, Taksu, Shigehara, Takaomi
We examine the quantum energy levels of rectangular billiards with a pointlike scatterer in one and two dimensions. By varying the location and the strength of the scatterer, we systematically find...