Results for "Masahide Sasaki"

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Retrodiction of Generalised Measurement OutcomesMay 15 2002Nov 01 2002If a generalised measurement is performed on a quantum system and we do not know the outcome, are we able to retrodict it with a second measurement? We obtain a necessary and sufficient condition for perfect retrodiction of the outcome of a known generalised ... More
Conditional generation of an arbitrary superposition of coherent statesFeb 13 2007We present a scheme to conditionally generate an arbitrary superposition of a pair of coherent states from a squeezed vacuum by means of the modified photon subtraction where a coherent state ancilla and two on/off type detectors are used. We show that, ... More
Photon number resolving detection at telecom wavelength with a charge integration photon detectorDec 09 2005We demonstrate multiphoton discrimination at telecom wavelength with the readout frequency of 40 Hz by charge integration photon detector (CIPD). The CIPD consists of an InGaAs pin photodiode and a GaAs junction field effect transistor as a pre-amplifier ... More
Quantum learning and universal quantum matching machineFeb 28 2002Suppose that three kinds of quantum systems are given in some unknown states $\ket f^{\otimes N}$, $\ket{g_1}^{\otimes K}$, and $\ket{g_2}^{\otimes K}$, and we want to decide which \textit{template} state $\ket{g_1}$ or $\ket{g_2}$, each representing ... More
Entangled state based on nonorthogonal stateJan 04 2001Properties of entangled states based on nonorthogonal states are clarified. Especially, it is shown that they can have complete degree of entanglement.
Multiphoton discrimination at telecom wavelength with charge integration photon detectorMar 04 2005We present a charge integration photon detector (CIPD) that enables the efficient measurement of photon number states at the telecom-fiber wavelengths with a quantum efficiency of 80% and a resolution less than 0.5 electrons at 1 Hz sampling. The CIPD ... More
Discrimination of the binary coherent signal: Gaussian-operation limit and simple non-Gaussian near-optimal receiversJun 07 2007Aug 14 2008We address the limit of the Gaussian operations and classical communication in the problem of quantum state discrimination. We show that the optimal Gaussian strategy for the discrimination of the binary phase shift keyed (BPSK) coherent signal is a simple ... More
The Quantumness of a Set of Quantum StatesFeb 13 2003This article is an introduction to quant-ph/0302092. We propose to quantify how "quantum" a set of quantum states is. The quantumness of a set is the worst-case difficulty of transmitting the states through a classical communication channel. Potential ... More
Wiretap Channels with Causal State Information: Strong SecrecyAug 01 2017Mar 23 2019The coding problem for wiretap channels with causal channel state information available at the encoder and/or the decoder is studied under the strong secrecy criterion. This problem consists of two aspects: one is due to naive wiretap channel coding and ... More
Squeezing Quantum Information through a Classical Channel: Measuring the "Quantumness" of a Set of Quantum StatesFeb 11 2003Jul 29 2003In this paper we propose a general method to quantify how "quantum" a set of quantum states is. The idea is to gauge the quantumness of the set by the worst-case difficulty of transmitting the states through a purely classical communication channel. Potential ... More
Supersymmetric DBI inflationMay 07 2012Oct 18 2012We discuss a supersymmetric version of DBI (Dirac-Born-Infeld) inflation, which is a typical inflation model in string cosmology. The supersymmetric DBI action together with a superpotential always leads to correction terms associated with the potential ... More
Invariance of the bit error rate in the ancilla-assisted homodyne detectionMar 22 2010We investigated the minimum achievable bit error rate of discriminating binary coherent states by homodyne measurements with the help of arbitrary ancilla states coupled via beam splitters. We took into account arbitrary pure ancillary states those were ... More
Reliability and Secrecy Functions of the Wiretap Channel under Cost ConstraintJul 02 2013Aug 19 2014The wiretap channel has been devised and studied first by Wyner, and subsequently extended to the case with non-degraded general wiretap channels by Csiszar and Korner. Focusing mainly on the Poisson wiretap channel with cost constraint, we newly introduce ... More
Cosmological Evolution of Global MonopolesMar 13 2001Aug 06 2001We investigate the cosmological evolution of global monopoles in the radiation dominated (RD) and matter dominated (MD) universes by numerically solving field equations of scalar fields. It is shown that the global monopole network relaxes into the scaling ... More
Supergravity based inflation models: a reviewJan 13 2011Apr 12 2011In this review, we discuss inflation models based on supergravity. After explaining the difficulties in realizing inflation in the context of supergravity, we show how to evade such difficulties. Depending on types of inflation, we give concrete examples, ... More
Natural Double Inflation in SupergravityMar 05 2001Jul 10 2001We propose a natural double inflation model in supergravity. In this model, chaotic inflation first takes place by virtue of the Nambu-Goldstone-like shift symmetry, which guarantees the absence of the exponential factor in the potential for the inflaton ... More
Unambiguous quantum state filteringApr 04 2003In this paper, we consider the generalized measurement where one particular quantum signal is unambiguously extracted from a set of non-commutative quantum signals and the other signals are filtered out. Simple expressions for the maximum detection probability ... More
Practical scheme for the optimal measuremnet in quantum interferometric devicesDec 06 2002Mar 26 2003We apply a Kennedy-type detection scheme, which was originally proposed for a binary communications system, to interferometric sensing devices. We show that the minimum detectable perturbation of the proposed system reaches the ultimate precision bound ... More
Ultrahigh-sensitivity high-linearity photodetection system using a low-gain avalanche photodiode with an ultralow-noise readout circuitMar 04 2005A highly sensitive photodetection system with a detection limit of 1 photon/s was developed. This system uses a commercially available 200-mm-diameter silicon avalanche photodiode (APD) and an in-house-developed ultralow-noise readout circuit, which are ... More
Temporally multiplexed superposition states of continuous variablesApr 02 2008Apr 08 2008We study non-Gaussian states generated by two-photon subtraction from a cw squeezed light source. In a cw scheme one can subtract two photons from the source with a designated time separation and can genarate temporally multiplexed superposition states ... More
On level 1 cyclotomic KLR algebras of type $A_{n}^{(1)}$May 16 2013We show some properties on a special case of level 1 cyclotomic KLR algebras of type $A_{n}^{(1)}$; the number of primitive idempotents, systematic change of structures, the dimension.
Experimental Determination of the Gain Distribution of an Avalanche Photodiode at Low GainsDec 04 2008A measurement system for determining the gain distributions of avalanche photodiodes (APDs) in a low gain range is presented. The system is based on an ultralow-noise charge--sensitive amplifier and detects the output carriers from an APD. The noise of ... More
Towards practical device-independent quantum key distribution with spontaneous parametric downconversion sources, on-off photodetectors and entanglement swappingDec 21 2015Jan 13 2016Device-independent quantum key distribution (DIQKD) guarantees unconditional security of secret key without making assumptions about the internal workings of the devices used. It does so using the loophole-free violation of a Bell's inequality. The primary ... More
Quantum channel of continuous variable teleportation and nonclassicality of quantum statesOct 05 2001Noisy teleportation of nonclassical quantum states via a two-mode squeezed-vacuum state is studied with the completely positive map and the Glauber-Sudarshan $P$-function. Using the nonclassical depth as a measure of transmission performance, we compare ... More
Optimal parameter estimation of depolarizing channelMar 22 2002We investigate strategies for estimating a depolarizing channel for a finite dimensional system. Our analysis addresses the double optimization problem of selecting the best input probe state and the measurement strategy that minimizes the Bayes cost ... More
Full analysis of multi-photon pair effects in spontaneous parametric down conversion based photonic quantum information processingOct 14 2014May 07 2015In spontaneous parametric down conversion (SPDC) based quantum information processing (QIP) experiments, there is a tradeoff between the coincide count rates (i.e. the pumping power of the SPDC), which limits the rate of the protocol, and the visibility ... More
Continuous variable teleportation as a generalized thermalizing quantum channelFeb 28 2002A quantum channel is derived for continuous variable teleportation which is performed by means of an arbitrary entangled state and the standard protocol. When a Gaussian entangled state such as a two-mode squeezed-vacuum state is used, the continuous ... More
Binary projective measurement via linear optics and photon countingMar 09 2006Mar 19 2006We investigate the implementation of binary projective measurements with linear optics. This problem can be viewed as a single-shot discrimination of two orthogonal pure quantum states. We show that any two orthogonal states can be perfectly discriminated ... More
Large amplitude coherent state superposition generated by a time-separated two-photon subtraction from a continuous wave squeezed vacuumApr 03 2008Jun 18 2008Theoretical analysis is given for a two-photon subtraction from a continuous wave (CW) squeezed vacuum with finite time separation between two detection events. In the CW photon subtraction process, the generated states are inevitably described by temporal ... More
Average Secrecy Capacity of Free-Space Optical Communication Systems with On-Off Keying Modulation and Threshold DetectionJan 24 2016This paper considers secure communication over free-space optical (FSO) links suffering from turbulence-induced fading. In particular, we study the average secrecy capacity of applying physical layer security to achieve security in an FSO communication ... More
Realization of a collective decoding of codeword statesJan 07 1998This was also extended from the previous article quant-ph/9705043, especially in a realization of the decoding process.
Entanglement evaluation of non-Gaussian states generated by photon subtraction from squeezed statesDec 09 2005Feb 22 2006We consider the problem of evaluating the entanglement of non-Gaussian mixed states generated by photon subtraction from entangled squeezed states. The entanglement measures we use are the negativity and the logarithmic negativity. These measures possess ... More
Unambiguous discrimination among oracle operatorsFeb 26 2007Jul 08 2007We address the problem of unambiguous discrimination among oracle operators. The general theory of unambiguous discrimination among unitary operators is extended with this application in mind. We prove that entanglement with an ancilla cannot assist any ... More
Entanglement quantification with Fisher informationDec 13 2006We show that the Fisher information associated with entanglement-assisted coding has a monotonic relationship with the logarithmic negativity, an important entanglement measure, for certain classes of continuous variable (CV) quantum states of practical ... More
Implementation of projective measurements with linear optics and continuous photon countingOct 18 2004Mar 04 2005We investigate the possibility of implementing a given projection measurement using linear optics and arbitrarily fast feedforward based on the continuous detection of photons. In particular, we systematically derive the so-called Dolinar scheme that ... More
Photon level crosstalk between parallel fibers installed in urban areaAug 05 2010We estimate the channel characteristics of field-installed dark fibers at single photon levels for quantum key distribution (QKD). Measured fibers are telecom single-mode dark fibers over 45 km connecting a center and suburbs of Tokyo. Their total losses ... More
Multi-channel SNSPD system with high detection efficiency at telecommunication wavelengthApr 01 2010We developed a four-channel superconducting nanowire single-photon detector system based on a Gifford-McMahon cryocooler. All channels showed a system detection efficiency (at a 100 Hz dark-count rate) higher than 16% at 1550 nm wavelength, and the best ... More
Compactly packaged superconducting nanowire single-photon detector with an optical cavity for multichannel systemFeb 28 2010We developed superconducting nanowire single-photon detectors with an optical cavity (OC-SNSPDs) for multichannel systems. For efficient coupling, the devices were installed in compact fiber-coupled packages after their substrate thickness was reduced ... More
Characteristics of superconducting single photon detector in DPS-QKD system under bright illumination blinding attackAug 10 2013We derive the time-dependent photo-detection probability equation of a superconducting single photon detector (SSPD) to study the responsive property for a pulse train at high repetition rate. Using this equation, we analyze the characteristics of SSPDs ... More
Numerical Study on Secrecy Capacity and Code Length Dependence of the Performances in Optical Wiretap ChannelsSep 14 2015Secrecy issues of free-space optical links realizing information theoretically secure communications as well as high transmission rates are discussed. We numerically study secrecy communication rates of optical wiretap channel based on on-off keying modulation ... More
7 dB quadrature squeezing at 860 nm with periodically-poled KTiOPO4Feb 03 2006Aug 15 2006We observed -7.2 dB quadrature squeezing at 860 nm by using a sub-threshold continuous-wave pumped optical parametric oscillator with a periodically-poled KTiOPO4 crystal as a nonlinear optical medium. The squeezing level was measured with the phase of ... More
Quantum channels showing superadditivity in capacityJan 08 1998This was significantly extended from the previous article quant-ph/9705043,especially in an information theoretic aspect, by adding new results.
Experimental demonstration of entanglement assisted coding using a two-mode squeezed vacuum stateFeb 05 2004Oct 29 2004We have experimentally realized the scheme initially proposed as quantum dense coding with continuous variables [Ban, J. Opt. B \textbf{1}, L9 (1999), and Braunstein and Kimble, \pra\textbf{61}, 042302 (2000)]. In our experiment, a pair of EPR (Einstein-Podolski-Rosen) ... More
Quantum receivers with squeezing and photon-number-resolving detectorsFeb 12 2013Apr 16 2013We propose quantum receivers with optical squeezing and photon-number-resolving detector (PNRD) for the near-optimal discrimination of quaternary phase-shift-keyed coherent state signals. The basic scheme is similar to the previous proposals (e.g. Phys. ... More
Exceeding classical capacity limit in quantum optical channelApr 04 2003The amount of information transmissible through a communications channel is determined by the noise characteristics of the channel and by the quantities of available transmission resources. In classical information theory, the amount of transmissible ... More
Wavelength division multiplexed and double-port pumped time-bin entangled photon pair generation using Si ring resonatorFeb 09 2017We report a wavelength division multiplexed time-bin entangled photon pair source in telecom wavelength using a 10 {\mu}m radius Si ring resonator. This compact resonator has two add ports and two drop ports. By pumping one add port by a continuous laser, ... More
Fidelity and the communication of quantum informationJul 05 2001We compare and contrast the error probability and fidelity as measures of the quality of the receiver's measurement strategy for a quantum communications system. The error probability is a measure of the ability to retrieve {\it classical} information ... More
Effective squeezing enhancement via measurement-induced non-Gaussian operation and its application to dense coding schemeMar 04 2005May 18 2005We study the measurement-induced non-Gaussian operation on the single- and two-mode \textit{Gaussian} squeezed vacuum states with beam splitters and on-off type photon detectors, with which \textit{mixed non-Gaussian} states are generally obtained in ... More
Development of SNSPD System with Gifford-McMahon CryocoolerMar 02 2010A superconducting nanowire single photon detector (SNSPD) system for telecommunication wavelength using a GM cryocooler was developed and its performance was verified. The cryocooler based SNSPD system can operate continuously with a 100 V AC power supply ... More
A simple quantum channel having superadditivity of channel capacityMay 26 1997When classical information is sent through a quantum channel of nonorthogonal states, there is a possibility that transmittable classical information exceeds a channel capacity in a single use of the initial channel by extending it into multi-product ... More
Open Virtual Structure Constants and Mirror Computation of Open Gromov-Witten Invariants of Projective HypersurfacesAug 24 2011In this paper, we generalize Walcher's computation of the open Gromov-Witten invariants of the quintic hypersurface to Fano and Calabi-Yau projective hypersurfaces. Our main tool is the open virtual structure constants. We also propose the generalized ... More
Primordial spectra from sudden turning trajectoryJul 26 2013Mar 25 2014Effects of heavy fields on primordial spectra of curvature perturbations are discussed in inflationary models with a sudden turning trajectory. When heavy fields are excited after the sudden turn and oscillate around the bottom of the potential, the following ... More
Runaway Domain Wall and Space-time Varying alphaFeb 01 2011Mar 31 2011Recently spatial as well as temporal variations of the fine structure constant alpha have been reported. We show that a "runaway domain wall", which arises for the scalar field potential without minima, can account for such variations simultaneously. ... More
Effects of Cosmic Strings on Free StreamingAug 10 2006We study the effect of free streaming in a universe with cosmic strings with time-varying tension as well as with constant tension. Although current cosmological observations suggest that fluctuation seeded by cosmic strings cannot be the primary source ... More
Supersymmetric topological inflation modelDec 06 2001Mar 29 2002We propose a topological inflation model in supergravity. In this model, the vacuum expectation value (VEV) of a scalar field takes a value much larger than the gravitational scale $M_{G} \simeq 2.4 \times 10^{18}$ GeV, which is large enough to cause ... More
Extended Open InflationJul 18 1999Dec 18 1999We present a new type of one-field models for open inflation utilizing a nonminimally coupled scalar field with polynomial potentials in which the Coleman-de Luccia instanton does exist and slow-roll inflation after the bubble nucleation is realized.
Multi-Point Virtual Structure Constants and Mirror Computation of CP^2-modelMay 05 2013In this paper, we propose a geometrical approach to mirror computation of genus 0 Gromov-Witten invariants of CP^2. We use multi-point virtual structure constants, which are defined as intersection numbers of a compact moduli space of quasi maps from ... More
Spontaneous baryogenesis in flat directionsAug 18 2003Apr 03 2004We discuss a spontaneous baryogenesis mechanism in flat directions. After identifying the Nambu-Goldstone mode which derivatively couples to the associated $U$(1) current and rotates due to the A-term, we show that spontaneous baryogenesis can be naturally ... More
Asymmetric Dark Matter from Spontaneous Cogenesis in the Supersymmetric Standard ModelJan 12 2012Jun 26 2012The observational relation between the density of baryon and dark matter in the Universe, $\Omega_{\rm DM}/\Omega_B\simeq 5$, is one of the most difficult problems to solve in modern cosmology. We discuss a scenario that explains this relation by combining ... More
Excited Baryon Spectroscopy from Lattice QCD: Finite Size Effect and Hyperfine Mass SplittingMar 19 2005Jul 01 2005A study of the finite-size effect is carried out for spectra of both ground-state and excited-state baryons in quenched lattice QCD using Wilson fermions. Our simulations are performed at beta=6.2 with three different spatial sizes, La~1.6, 2.2 and 3.2 ... More
Quantitative evolution of global strings from the Lagrangian viewpointOct 24 2002May 01 2003We clarify the quantitative nature of the cosmological evolution of a global string network, that is, the energy density, peculiar velocity, velocity squared, Lorentz factor, formation rate of loops, and emission rate of Nambu-Goldstone bosons, based ... More
Evolution and thermalization of dark matter axions in the condensed regimeOct 26 2012Apr 15 2013We discuss the possibility that dark matter axions form a Bose-Einstein condensate (BEC) due to the gravitational self-interactions. The formation of BEC occurs in the condensed regime, where the transition rate between different momentum states is large ... More
Probability Distribution Function of the Coarse-grained Scalar Field at Finite TemperatureMay 15 1998We present a formalism to calculate the probability distribution function of a scalar field coarse-grained over some spatial scales with a Gaussian filter at finite temperature. As an application, we investigate the role of subcritical fluctuations in ... More
Numerical approach to the onset of the electroweak phase transitionJul 29 1997Jul 31 1997We investigate whether the universe was homogeneously in the false vacuum state at the critical temperature of a weakly first-order phase transition such as the electroweak phase transition in terms of a series of numerical simulations of a phenomenological ... More
Smooth hybrid inflation in supergravity with a running spectral index and early star formationFeb 26 2004Jul 14 2004It is shown that in a smooth hybrid inflation model in supergravity adiabatic fluctuations with a running spectral index with $\ns >1$ on a large scale and $\ns <1$ on a smaller scale can be naturally generated, as favored by the first-year data of WMAP. ... More
New inflation in supergravity with a chaotic initial conditionJul 04 2000Jan 10 2001We propose a self-consistent scenario of new inflation in supergravity. Chaotic inflation first takes place around the Planck scale, which solves the longevity problem, namely, why the universe can live much beyond the Planck time, and also gives an adequate ... More
Experimental realization of optimal detection strategies for overcomplete statesAug 04 2000Mar 05 2001We present the results of generalized measurements of optical polarization designed to provide one of three or four distinct outcomes. This has allowed us to discriminate between nonorthogonal polarization states with an error probability that is close ... More
Quantum receiver beyond the standard quantum limit of coherent optical communicationMar 29 2011The most efficient modern optical communication is known as coherent communication and its standard quantum limit (SQL) is almost reachable with current technology. Though it has been predicted for a long time that this SQL could be overcome via quantum ... More
Sub-shot-noise-limit discrimination of on-off keyed coherent signals via a quantum receiver with a superconducting transition edge sensorFeb 15 2010We demonstrate a sub-shot-noise-limit discrimination of on-off keyed coherent signals by an optimal displacement quantum receiver in which a superconducting transition edge sensor is installed. Use of a transition edge sensor and a fiber beam splitter ... More
QKD from a microsatellite: the SOTA experienceOct 26 2018The transmission and reception of polarized quantum-limited signals from space is of capital interest for a variety of fundamental-physics experiments and quantum-communication protocols. Specifically, Quantum Key Distribution (QKD) deals with the problem ... More
Widely tunable single photon source with high purity at telecom wavelengthMar 25 2013We theoretically and experimentally investigate the spectral tunability and purity of photon pairs generated from spontaneous parametric down conversion in periodically poled $\mathrm{KTiOPO_4}$ crystal with group-velocity matching condition. The numerical ... More
Nonlinear curvature perturbations in an exactly soluble model of multi-component slow-roll inflationFeb 07 2007Mar 27 2007Using the nonlinear $\delta N$ formalism, we consider a simple exactly soluble model of multi-component slow-roll inflation in which the nonlinear curvature perturbation can be evaluated analytically.
Post-Newtonian Expansion of the Ingoing-Wave Regge-Wheeler FunctionFeb 24 1994We present a method of post-Newtonian expansion to solve the homogeneous Regge-Wheeler equation which describes gravitational waves on the Schwarzschild spacetime. The advantage of our method is that it allows a systematic iterative analysis of the solution. ... More
Hyperon vector form factor from 2+1 flavor lattice QCDSep 27 2012Nov 26 2012We present the first result for the hyperon vector form factor f_1 for Xi^0 -> Sigma^+ l bar{nu} and Sigma^- -> n l bar{nu} semileptonic decays from fully dynamical lattice QCD. The calculations are carried out with gauge configurations generated by the ... More
Energy Spectra for Fractional Quantum Hall StatesAug 11 2007Fractional quantum Hall states (FQHS) with the filling factor nu = p/q of q < 21 are examined and their energies are calculated. The classical Coulomb energy is evaluated among many electrons; that energy is linearly dependent on 1/nu. The residual binding ... More
Pentaquarks: Status and Perspectives for Lattice CalculationsOct 13 2004The present status of pentaquark spectroscopy in lattice QCD is reviewed. This talk also includes a brief introduction of pentaquark baryons.
Lattice study of nucleon properties with domain wall fermionsOct 12 2001Domain wall fermions (DWF) are a new fermion discretization scheme with greatly improved chiral symmetry. Our final goal is to study the nucleon spin structure through lattice simulation using DWF. In this paper, we present our current progress on two ... More
Intracluster Supernova as a Possible Extra Energy Source of ClustersNov 09 2000The observed luminosity -- temperature relation of clusters is considerably steeper than that expected from a simple scaling relation. Although extra energy input is a likely solution, its source has not been identified. We propose intracluster supernova ... More
Hyperon vector coupling f_1(0) from 2+1 flavor lattice QCDFeb 24 2011We present results for the hyperon vector form factor f_1 for $\Xi^0 \rightarrow \Sigma^+ l\bar{\nu}$ and $\Sigma^- \rightarrow n l\bar{\nu}$ semileptonic decays from dynamical lattice QCD with domain-wall quarks. Simulations are performed on the 2+1 ... More
New Quasi Exactly Solvable Difference EquationDec 17 2007Exact solvability of two typical examples of the discrete quantum mechanics, i.e. the dynamics of the Meixner-Pollaczek and the continuous Hahn polynomials with full parameters, is newly demonstrated both at the Schroedinger and Heisenberg picture levels. ... More
Affine Lie Algebras and S-Duality of N=4 Super Yang-Mills Theory for ADE Gauge Groups on K3Apr 24 2004May 04 2004We attempt to determine the partition function of ${\cal N}=4$ super Yang-Mills theory for $ADE$ gauge groups on $K3$ and investigate the relation with affine Lie algebras. In particular we describe eta functions, which compose SU(N) partition function, ... More
Symmetric Morse potential is exactly solvableNov 18 2016Nov 28 2016Morse potential $V_M(x)= g^2\exp (2x)-g(2h+1)\exp(x)$ is defined on the full line, $-\infty<x<\infty$ and it defines an exactly solvable 1-d quantum mechanical system with finitely many discrete eigenstates. By taking its right half $0\le x<\infty$ and ... More
Limits and Singularities of Normal FunctionsSep 15 2018We construct a collection of higher Chow cycles on certain surfaces which degenerate to an arrangement of planes in general position. When its degree is 4, this construction gives a new explicit proof of the Hodge-D-Conjecture for a certain type of K3 ... More
One Particle Binding of Many-Particle Semi-Relativistic Pauli-Fierz ModelMar 20 2013Mar 25 2013It is shown that at least one particle is bound in the $N$-particle semi-relativistic Pauli-Fierz model with negative potential $V(\bx)$. It is assumed that the particles have no spin and obey the Bose or Boltzmann statistics, and the one particle Hamiltonian ... More
Consideration of ac Josephson Effect in Fractional Quantum Hall StatesJul 02 2008The ac Josephson effect phenomenon is studied in fractional quantum Hall states (FQHS). Usual quantum Hall devices have an electron layer of uniform thickness. We consider a new quantum Hall device. The device has a narrow part that is vertical to the ... More
Calculation of Binding Energies for Fractional Quantum Hall States with Even DenominatorsMar 14 2007Fractional quantum Hall states with even denominators have the following specific properties: states with filling factors nu=5/8, 7/10, 3/8, 3/10, and so on have respective local minima in the experimental curve of diagonal resistivity Rxx versus magnetic ... More
Exactly solvable potentials with finitely many discrete eigenvalues of arbitrary choiceFeb 22 2014We address the problem of possible deformations of exactly solvable potentials having finitely many discrete eigenvalues of arbitrary choice. As Kay and Moses showed in 1956, reflectionless potentials in one dimensional quantum mechanics are exactly solvable. ... More
Reflection Bootstrap Equations for Toda Field TheoryNov 04 1993An algebraic approach to integrable quantum field theory with a boundary (a half line) is presented and interesting algebraic equations, Reflection equations (RE) and Reflection Bootstrap equations (RBE) are discussed. The Reflection equations are a consistent ... More
Symmetric Morse potential is exactly solvableNov 18 2016Morse potential $V_M(x)= g^2\exp (2x)-g(2h+1)\exp(x)$ is defined on the full line, $-\infty<x<\infty$ and it defines an exactly solvable 1-d quantum mechanical system with finitely many discrete eigenstates. By taking its right half $0\le x<\infty$ and ... More
The evolution of cooperation through institutional incentives and optional participationFeb 27 2013Rewards and penalties are common practical tools that can be used to promote cooperation in social institutions. The evolution of cooperation under reward and punishment incentives in joint enterprises has been formalized and investigated, mostly by using ... More
Gap Condition and Self-Dualized ${\cal N}=4$ Super Yang-Mills Theory for ADE Gauge Group on K3Mar 20 2003Apr 21 2003We try to determine the partition function of ${\cal N}=4$ super Yang-Mills theoy for ADE gauge group on K3 by self-dualizing our previous ADE partition function. The resulting partition function satisfies gap condition.
Hecke Operator and S-Duality of N=4 Super Yang-Mills for ADE Gauge Group on K3Mar 13 2003Jul 14 2003We determine the partition functions of ${\cal N}=4$ super Yang-Mills gauge theory for some $ADE$ gauge groups on $K3$, under the assumption that they are holomorphic. Our partition functions satisfy the gap condition and Montonen-Olive duality at the ... More
Molecular Chemical Engines: Pseudo-Static Processes and the Mechanism of Energy TransductionAug 01 2005We propose a simple theoretical model for a molecular chemical engine that catalyzes a chemical reaction and converts the free energy released by the reaction into mechanical work. Binding and unbinding processes of reactant and product molecules to and ... More
Gauge-independent Thermal $β$ Function In Yang-Mills Theory via the Pinch TechniqueDec 27 1995Jan 12 1996It is proposed to use the pinch technique (PT) to obtain the gauge-independent thermal $\beta$ function $\beta_T$ in a hot Yang-Mills gas. Calculations of the thermal $\beta$ function are performed at one-loop level in four different gauges, (i) the background ... More
Charge Screening Effect in Metallic Carbon NanotubesDec 11 2001Charge screening effect in metallic carbon nanotubes is investigated in a model including the one-dimensional long-range Coulomb interaction. It is pointed out that an external charge which is being fixed spatially is screened by internal electrons so ... More
Vacuum structure of Toroidal Carbon NanotubesJun 11 2001Oct 12 2001Low energy excitations in carbon nanotubes can be described by an effective field theory of two components spinor. It is pointed out that the chiral anomaly in 1+1 dimensions should be observed in a metallic toroidal carbon nanotube on a planar geometry ... More
On link diagrams that are minimal with respect to Reidemeister moves I and IIDec 02 2016In this paper, a link diagram is said to be minimal if no Reidemeister move I or II can be applied to it to reduce the number of crossings. We show that for an arbitrary diagram D of a link without a trivial split component, a minimal diagram obtained ... More
Inverse scattering for the nonlinear Schrödinger equation with the Yukawa potentialNov 05 2007Jun 25 2008We study the inverse scattering problem for the three dimensional nonlinear Schroedinger equation with the Yukawa potential. The nonlinearity of the equation is nonlocal. We reconstruct the potential and the nonlinearity by the knowledge of the scattering ... More
Optimal conditions for Bell test using spontaneous parametric down-conversion sourcesAug 25 2018We theoretically and experimentally investigate the optimal conditions for the Bell experiment using spontaneous parametric down conversion (SPDC) sources. In theory, we show that relatively large average photon number (typically $\sim$0.5) is desirable ... More
Maintenance-free Operation of WDM Quantum Key Distribution System through a Field Fiber over 30 DaysAug 05 2013Maintenance-free wavelength-division-multiplexing quantum key distribution for 30 days was achieved through a 22-km field fiber. Using polarization-independent interferometers and stabilization techniques, we attained a quantum bit error rate as low as ... More