In Hyun Nahm - Academia.edu (original) (raw)
Papers by In Hyun Nahm
Journal of Physics: Condensed Matter, Jun 12, 1989
The wavelength dependence of quantum interference corrections to the diffusion constant is calcul... more The wavelength dependence of quantum interference corrections to the diffusion constant is calculated in two dimensions, in the weak-localisation regime, using models belonging to the three universality classes for localisation. In each case, the corrections at second order in perturbation theory are much larger for finite wavevector than expected from previous results at zero wavevector. In two cases (systems without time-reversal invariance and systems with spin-orbit scattering), this wavevector dependence determines the way in which perturbation theory breaks down as the cut-off length for quantum interference increases. The authors speculate that these results may signal crossover from simple diffusive behaviour to a critical regime characterised by novel variation of the diffusion constant with wavevector and frequency.
Journal of Physics: Condensed Matter, Sep 14, 1992
The distribution of eigenfunction nodes in a disordered electron system under a strong perpendicu... more The distribution of eigenfunction nodes in a disordered electron system under a strong perpendicular magnetic field is studied. It is demonstrated that the distribution of eigenfunction nodes is closely related to the amplitude correlation of the eigenfunction in such a state. For the distribution of nodes the author obtained a formula fitting the numerical result, suggesting that the distribution is somewhere between the binomial distribution and the Poisson distribution.
Pramana, 2009
We examine whether the general type Fock-state wave functions for the harmonic oscillator have so... more We examine whether the general type Fock-state wave functions for the harmonic oscillator have some relations with the classical initial condition.
International Journal of Theoretical Physics, 2006
Exact quantum states of the time-dependent quadratic Hamiltonian system are investigated using SU... more Exact quantum states of the time-dependent quadratic Hamiltonian system are investigated using SU(1,1) Lie algebra. We realized SU(1,1) Lie algebra by defining appropriate SU(1,1) generators and derived exact wave functions using this algebra for the system. Raising and lowering operators of SU(1,1) Lie algebra expressed by multiplying a time-constant magnitude and a time-dependent phase factor. Two kinds of the SU(1,1) coherent states, i.e., even and odd coherent states and Perelomov coherent states are studied. We applied our result to the Caldirola-Kanai oscillator. The probability density of these coherent states for the Caldirola-Kanai oscillator converged to the center as time goes by, due to the damping constant γ. All the coherent state probability densities for the driven system are somewhat deformed.
Annals of Physics, 2011
... Soo Kim, Daeyeoul Kim, Mustapha Maamache, and In Hyun Nahm 1. Information theories for the ge... more ... Soo Kim, Daeyeoul Kim, Mustapha Maamache, and In Hyun Nahm 1. Information theories for the general time-dependent harmonic oscillator based on invariant operator method. 2. Time dependence of entropies and entropic uncertainty relation 3. Characteristics of Shannon ...
Journal of Applied Physics, 2000
ABSTRACT
Modern Physics Letters B, 2006
The classical equations of motion for the dissipative RLC coupled two-dimensional circuit with a ... more The classical equations of motion for the dissipative RLC coupled two-dimensional circuit with a power source are solved using two-step canonical transformation. We applied our investigation to the system whose power source is the form of sinusoidally oscillating with time.
Journal of Physics: Condensed Matter, 1993
ABSTRACT The critical behaviour of wavefunctions at the Anderson metal-insulator transition is st... more ABSTRACT The critical behaviour of wavefunctions at the Anderson metal-insulator transition is studied by numerical simulation, using as an example of a system with a mobility edge a two-dimensional tight-binding model with spin-orbit scattering. It is demonstrated that individual eigenstates have multifractal fluctuations of their probability density. The influence of these fluctuations on the two-particle correlations is examined via calculations of the wavevector and frequency dependence of the diffusion constant.
Ijmpb, 2006
Uncertainty relations for the time-dependent singular oscillator in the number state and in the c... more Uncertainty relations for the time-dependent singular oscillator in the number state and in the coherent state are investigated. We applied our developement to the Caldirola–Kanai oscillator perturbed by a singularity. For this system, the variation (Δx) decreased exponentially while (Δp) increased exponentially with time both in the number and in the coherent states. As k → 0 and χ → 0, the number state uncertainty relation in the ground state becomes 0.583216ℏ which is somewhat larger than that of the standard harmonic oscillator, ℏ/2. On the other hand, the uncertainty relation in all excited states become smaller than that of the standard harmonic oscillator with the same quantum number n. However, as k → ∞ and χ → 0, the uncertainty relations of the system approach the uncertainty relations of the standard harmonic oscillator, (n+1/2)ℏ.
Nonclassical properties of a Schrodinger cat state are investigated for the electromagnetic field... more Nonclassical properties of a Schrodinger cat state are investigated for the electromagnetic field in linear media that have time-dependent parameters via the Wigner distribution function. Application to a particular system is given in order for better understanding on nonclassicality of the quantum system. Negative values that signifies nonclassical features of the system are appeared in Wigner distribution function as interference structure. In some cases, Wigner distribution function is severely distorted on account of time-dependence of parameters.
Journal of Physics: Condensed Matter, Jun 12, 1989
The wavelength dependence of quantum interference corrections to the diffusion constant is calcul... more The wavelength dependence of quantum interference corrections to the diffusion constant is calculated in two dimensions, in the weak-localisation regime, using models belonging to the three universality classes for localisation. In each case, the corrections at second order in perturbation theory are much larger for finite wavevector than expected from previous results at zero wavevector. In two cases (systems without time-reversal invariance and systems with spin-orbit scattering), this wavevector dependence determines the way in which perturbation theory breaks down as the cut-off length for quantum interference increases. The authors speculate that these results may signal crossover from simple diffusive behaviour to a critical regime characterised by novel variation of the diffusion constant with wavevector and frequency.
Journal of Physics: Condensed Matter, Sep 14, 1992
The distribution of eigenfunction nodes in a disordered electron system under a strong perpendicu... more The distribution of eigenfunction nodes in a disordered electron system under a strong perpendicular magnetic field is studied. It is demonstrated that the distribution of eigenfunction nodes is closely related to the amplitude correlation of the eigenfunction in such a state. For the distribution of nodes the author obtained a formula fitting the numerical result, suggesting that the distribution is somewhere between the binomial distribution and the Poisson distribution.
Pramana, 2009
We examine whether the general type Fock-state wave functions for the harmonic oscillator have so... more We examine whether the general type Fock-state wave functions for the harmonic oscillator have some relations with the classical initial condition.
International Journal of Theoretical Physics, 2006
Exact quantum states of the time-dependent quadratic Hamiltonian system are investigated using SU... more Exact quantum states of the time-dependent quadratic Hamiltonian system are investigated using SU(1,1) Lie algebra. We realized SU(1,1) Lie algebra by defining appropriate SU(1,1) generators and derived exact wave functions using this algebra for the system. Raising and lowering operators of SU(1,1) Lie algebra expressed by multiplying a time-constant magnitude and a time-dependent phase factor. Two kinds of the SU(1,1) coherent states, i.e., even and odd coherent states and Perelomov coherent states are studied. We applied our result to the Caldirola-Kanai oscillator. The probability density of these coherent states for the Caldirola-Kanai oscillator converged to the center as time goes by, due to the damping constant γ. All the coherent state probability densities for the driven system are somewhat deformed.
Annals of Physics, 2011
... Soo Kim, Daeyeoul Kim, Mustapha Maamache, and In Hyun Nahm 1. Information theories for the ge... more ... Soo Kim, Daeyeoul Kim, Mustapha Maamache, and In Hyun Nahm 1. Information theories for the general time-dependent harmonic oscillator based on invariant operator method. 2. Time dependence of entropies and entropic uncertainty relation 3. Characteristics of Shannon ...
Journal of Applied Physics, 2000
ABSTRACT
Modern Physics Letters B, 2006
The classical equations of motion for the dissipative RLC coupled two-dimensional circuit with a ... more The classical equations of motion for the dissipative RLC coupled two-dimensional circuit with a power source are solved using two-step canonical transformation. We applied our investigation to the system whose power source is the form of sinusoidally oscillating with time.
Journal of Physics: Condensed Matter, 1993
ABSTRACT The critical behaviour of wavefunctions at the Anderson metal-insulator transition is st... more ABSTRACT The critical behaviour of wavefunctions at the Anderson metal-insulator transition is studied by numerical simulation, using as an example of a system with a mobility edge a two-dimensional tight-binding model with spin-orbit scattering. It is demonstrated that individual eigenstates have multifractal fluctuations of their probability density. The influence of these fluctuations on the two-particle correlations is examined via calculations of the wavevector and frequency dependence of the diffusion constant.
Ijmpb, 2006
Uncertainty relations for the time-dependent singular oscillator in the number state and in the c... more Uncertainty relations for the time-dependent singular oscillator in the number state and in the coherent state are investigated. We applied our developement to the Caldirola–Kanai oscillator perturbed by a singularity. For this system, the variation (Δx) decreased exponentially while (Δp) increased exponentially with time both in the number and in the coherent states. As k → 0 and χ → 0, the number state uncertainty relation in the ground state becomes 0.583216ℏ which is somewhat larger than that of the standard harmonic oscillator, ℏ/2. On the other hand, the uncertainty relation in all excited states become smaller than that of the standard harmonic oscillator with the same quantum number n. However, as k → ∞ and χ → 0, the uncertainty relations of the system approach the uncertainty relations of the standard harmonic oscillator, (n+1/2)ℏ.
Nonclassical properties of a Schrodinger cat state are investigated for the electromagnetic field... more Nonclassical properties of a Schrodinger cat state are investigated for the electromagnetic field in linear media that have time-dependent parameters via the Wigner distribution function. Application to a particular system is given in order for better understanding on nonclassicality of the quantum system. Negative values that signifies nonclassical features of the system are appeared in Wigner distribution function as interference structure. In some cases, Wigner distribution function is severely distorted on account of time-dependence of parameters.