Lee, Minchul, Choi, Mahn-Soo, Lopez, Rosa, Aguado, Ramon, Martinek, Jan, Zitko, Rok
We study a series-coupled double quantum dot in the Kondo regime modeled by the two-impurity Anderson model and find a new conduction-band mediated superexchange interaction that competes with Kondo...
Conductance of tubular nanowires with disorder (2009)
Serra, Llorens, Choi, Mahn-Soo
We calculate the conductance of tubular-shaped nanowires having many potential scatterers at random positions. Our approach is based on the scattering matrix formalism and our results analyzed within...
Hardy's Test versus the CHSH Test of Quantum Non-Locality: Fundamental and Practical Aspects (2008)
We compare two different tests of quantum non-locality, both in theoretical terms and with respect to a possible implementation in a mesoscopic circuit: Hardy's test [Hardy, Phys. Rev. Lett....
Strongly modulated transmission of a spin-split quantum wire with local Rashba interaction (2007)
Sanchez, David, Serra, Llorens, Choi, Mahn-Soo
We investigate the transport properties of ballistic quantum wires in the presence of Zeeman spin splittings and a spatially inhomogeneous Rashba interaction. The Zeeman interaction is extended along...
Nanospintronics with carbon nanotubes (2007)
Cottet, Audrey, Kontos, Takis, Sahoo, Sangeeta, Man, Hon Tin, Choi, Mahn-Soo, Belzig, Wolfgang, ...
One of the actual challenges of spintronics is the realization of a spin-transistor allowing to control spin transport through an electrostatic gate. In this review, we report on different...
Quantum Key Distribution Using Quantum Faraday Rotators (2006)
Choi, Taeseung, Choi, Mahn-Soo
We propose a new quantum key distribution (QKD) protocol based on the fully quantum mechanical states of the Faraday rotators. The protocol is unconditionally secure against collective attacks for...
Magnetoresistance of a quantum dot with spin-active interfaces (2006)
Cottet, Audrey, Choi, Mahn-Soo
We study the zero-bias magnetoresistance (MR) of an interacting quantum dot connected to two ferromagnetic leads and capacitively coupled to a gate voltage source Vg. We investigate the effects of...
Quantum Dissipative Dynamics of Entanglement in the Spin-Boson Model (2006)
Lim, Jong Soo, Choi, Mahn-Soo, Choi, M. Y.
We study quantum dissipative dynamics of entanglement in the spin-boson model, described by the generalized master equation. We consider the two opposite limits of pure-dephasing and relaxation...
Andreev Bound States in the Kondo Quantum Dots Coupled to Superconducting Leads (2006)
We have studied the Kondo quantum dot coupled to two superconducting leads and investigated the subgap Andreev states using the NRG method. Contrary to the recent NCA results [Clerk and Ambegaokar,...
Pair Tunneling and shot noise through a single molecule in a strong electron-phonon coupling (2006)
Hwang, Myung-Joong, Choi, Mahn-Soo, Lopez, Rosa
We investigate the electronic transport through a single molecule in a strong electron-phonon coupling regime. Based on a particle-hole transformation which is made suitable for non-equilibrium...
Kondo Effects in Carbon Nanotubes: From SU(4) to SU(2) symmetry (2006)
Lim, Jong Soo, Choi, Mahn-Soo, Choi, M. Y., Lopez, Rosa, Aguado, Ramon
We study the Kondo effect in a single-electron transistor device realized in a single-wall carbon nanotube. The K-K' double orbital degeneracy of a nanotube, which originates from the peculiar...
Quantum-based Mechanical Force Realization in Pico-Newton Range (2006)
Choi, Jae-Hyuk, Kim, Min-Seok, Park, Yon-Kyu, Choi, Mahn-Soo
We propose mechanical force realization based on flux quantization in the pico-Newton range. By controlling the number of flux quantum in a superconducting annulus, a force can be created as integer...
Magnetoresistance of a quantum dot with spin-active interfaces (2006)
Cottet, Audrey, Choi, Mahn-Soo
We study the zero-bias magnetoresistance MR of an interacting quantum dot connected to two ferromagnetic leads and capacitively coupled to a gate voltage source Vg. We investigate the effects of the...
Mesoscopic Kondo effects in nanoscale systems (2006)
A few selected topics on the Kondo effects in mesoscopic systems have been reviewed. Included are the effects of the competition of the spin polarisation and the superconductivity with the Kondo...
Mesoscopic Kondo effects in nanoscale systems (2006)
A few selected topics on the Kondo effects in mesoscopic systems have been reviewed. Included are the effects of the competition of the spin polarisation and the superconductivity with the Kondo...
Spin-Hall effect: Back to the Beginning on a Higher Level (2005)
Sinova, Jairo, Murakami, Shuichi, Shen, Shun-Qing, Choi, Mahn-Soo
The phenomena of the spin-Hall effect, initially proposed over three decades ago in the context of asymmetric Mott skew scattering, was revived recently by the proposal of a possible intrinsic...
Decoherence Driven Quantum Transport (2005)
Kim, Sang Wook, Choi, Mahn-Soo
We propose a new mechanism to generate a dc current of particles at zero bias based on a noble interplay between coherence and decoherence. We show that a dc current arises if the transport process...
Spintronic transport and Kondo effect in quantum dots (2005)
Sanchez, David, Lopez, Rosa, Choi, Mahn-Soo
We investigate the spin-dependent transport properties of quantum-dot based structures where Kondo correlations dominate the electronic dynamics. The coupling to ferromagnetic leads with parallel...
Nonequilibrium plasmons and transport properties of a double--junction quantum wire (2005)
Kim, Jaeuk U., Choi, Mahn-Soo, Krive, Ilya V., Kinaret, Jari M.
We study theoretically the current-voltage characteristics, shot noise, and full counting statistics of a quantum wire double barrier structure. We model each wire segment by a spinless Luttinger...
Comment on "Josephson Current through a Nanoscale Magnetic Quantum Dot" (2005)
Choi, Mahn-Soo, Lee, Minchul, Kang, Kicheon, Belzig, Wolfgang
SU(4) Kondo Effect in Carbon Nanotubes (2004)
Choi, Mahn-Soo, Lopez, Rosa, Aguado, Ramon
We investigate theoretically the non-equilibrium transport properties of carbon nanotube quantum dots. Owing to the two-dimensional band structure of graphene, a double orbital degeneracy plays the...
Comment on "Josephson Current through a Nanoscale Magnetic Quantum Dot" (2004)
Choi, Mahn-Soo, Lee, Minchul, Kang, Kecheon, Belzig, W.
In a recent work [Phys. Rev. Lett. 93, 047002 (2004)], Siano and Egger (SE) studied Josephson current through a quantum dot in the Kondo regime using the quantum Monte Carlo (QMC) method. Several of...
Ballistic spin currents in mesoscopic metal/In(Ga)As/metal junctions (2004)
We investigate the ballistic spin transport through a two-dimensional mesoscopic metal/semiconductor/metal double junctions in the presence of spin-orbit interactions. It is shown that \emph{real}...
Kim, Jaeuk U., Kinaret, Jari M., Choi, Mahn-Soo
We consider a quantum wire double junction system with each wire segment described by a spinless Luttinger model, and study theoretically shot noise in this system in the sequential tunneling regime....
Probing spin and orbital Kondo effects with a mesoscopic interferometer (2004)
Lopez, Rosa, Sanchez, David, Lee, Minchul, Choi, Mahn-Soo, Simon, Pascal, Hur, Karyn Le
We investigate theoretically the transport properties of a closed Aharonov-Bohm interferometer containing two quantum dots in the strong coupling regime. We find two distinct physical scenarios...
Kondo effect and Josephson current through a quantum dot between two superconductors (2004)
Choi, Mahn-Soo, Lee, Minchul, Kang, Kicheon, Belzig, Wolfgang
We investigate the supercurrent through a quantum dot for the whole range of couplings using the numerical renormalization group method. We find that the Josephson current switches abruptly from a p-...
Kondo Effect and Josephson Current through a Quantum Dot between Two Superconductors (2003)
Choi, Mahn-Soo, Lee, Minchul, Kang, Kicheon, Belzig, W.
We investigate the supercurrent through a quantum dot for the whole range of couplings using the numerical renormalization group method. We find that the Josephson current switches abruptly from a...
Gassmann, Hanno, Choi, Mahn-Soo, Yi, Hangmo, Bruder, C.
We study a model of a magnetic resonance force microscope (MRFM) based on the cyclic adiabatic inversion technique as a high-resolution tool to detect single electron spins. We investigate the...
Choi, Mahn-Soo, Sanchez, David, Lopez, Rosa
We investigate the effects of spin-polarized leads on the Kondo physics of a quantum dot using the numerical renormalization group method. Our study demonstrates in an unambiguous way that the Kondo...
Quantum Phase Transitions and Persistent Currents in Josephson-Junction Ladders (2003)
Lee, Minchul, Choi, Mahn-Soo, Choi, M. Y.
In this work we study quantum phase transitions and persistent currents in capacitively coupled one-dimensional Josephson-junction arrays. We will focus particularly on the roles of exciton-like...
Kondo Effect of Quantum Dots in the Quantum Hall Regime (2002)
Choi, Mahn-Soo, Hwang, Nak Yeon, Yang, S. -R. Eric
Quantum dots in the quantum Hall regime can have pairs of single Slater determinant states that are degenerate in energy. We argue that these pairs of many body states may give rise to a Kondo effect...
Effect of Quantum Fluctuations in an Ising System on Small-World Networks (2002)
We study quantum Ising spins placed on small-world networks. A simple model is considered in which the coupling between any given pair of spins is a nonzero constant if they are linked in the...
Choi, Mahn-Soo, Plastina, Francesco, Fazio, Rosario
We analyze charge tunneling statistics and current noise in a superconducting single-electron transistor in a regime where the Josephson-quasiparticle cycle is the dominant mechanism of transport....
Geometric Quantum Computation on Solid-State Qubits (2001)
An adiabatic cyclic evolution of control parameters of a quantum system ends up with a holonomic operation on the system, determined entirely by the geometry in the parameter space. The operation is...
Coherent oscillations in a Cooper-pair box (2001)
Choi, Mahn-Soo, Fazio, Rosario, Siewert, Jens, Bruder, C.
This paper is devoted to an analysis of the experiment by Nakamura {\it et al.} (Nature {\bf 398}, 786 (1999)) on the quantum state control in Josephson junctions devices. By considering the relevant...
Shot noise for resonant Cooper pair tunneling (2001)
Choi, Mahn-Soo, Plastina, Francesco, Fazio, Rosario
We study intrinsic noise of current in a superconducting single-electron transistor, taking into account both coherence effects and Coulomb interaction near a Cooper-pair resonance. Due to this...
Spatiotemporal Stochastic Resonance in Fully Frustrated Josephson Ladders (2000)
Kim, Beom Jun, Choi, Mahn-Soo, Minnhagen, Petter, Jeon, Gun Sang, Kim, H. J., Choi, M. Y.
We consider a Josephson-junction ladder in an external magnetic field with half flux quantum per plaquette. When driven by external currents, periodic in time and staggered in space, such a fully...
Anderson-type model for a molecule adsorbed on a metal surface (2000)
We investigate a modified Anderson model to study the local density of states (LDOS) of a molecular wire adsorbed on a metal. Using a self-consistent mean-field type approach we find an exponential...
Choi, Mahn-Soo, Bruder, C., Loss, Daniel
We study a double quantum dot each dot of which is tunnel-coupled to superconducting leads. In the Coulomb blockade regime, a spin-dependent Josephson coupling between two superconductors is induced,...
Charge Frustration Effects in Capacitively Coupled Two-Dimensional Josephson-Junction Arrays (1999)
Lee, Minchul, Choi, Mahn-Soo, Choi, M. Y.
We investigate the quantum phase transitions in two capacitively coupled two-dimensional Josephson-junction arrays with charge frustration. The system is mapped onto the S=1 and $S=1/2$ anisotropic...
Quantum Phase Transitions in Capacitively Coupled Two-Dimensional Josephson-Junction Arrays (1998)
Quantum-phase transitions in two layers of ultrasmall Josephson junctions, coupled capacitively with each other, are investigated. As the interlayer capacitance is increased, the system at zero...
Current responses and voltage fluctuations in Josephson-junction systems (1998)
Choi, Mahn-Soo, Choi, M. Y., Lee, Sung-Ik
We consider arrays of Josephson junctions as well as single junctions in both the classical and quantum-mechanical regimes, and examine the generalized (frequency-dependent) resistance, which...
Choi, Mahn-Soo, Choi, M. Y., Choi, Taeseung, Lee, Sung-Ik
We investigate the quantum phase transitions in two capacitively coupled chains of ultra-small Josephson-junctions, with emphasis on the external charge effects. The particle-hole symmetry of the...
Capacitively coupled Josephson-junction chains: straight and slanted coupling (1998)
Two chains of ultrasmall Josephson junctions, coupled capacitively with each other in the two different ways, straight and slanted coupling, are considered. As the coupling capacitance increases,...
Choi, Mahn-Soo, Choi, M. Y., Lee, Sung-Ik
We consider two chains of ultrasmall Josephson junctions, coupled capacitively with each other, and investigate the transport of particle-hole pairs and the quantum phase transitions at zero...
Quantum Phase Transitions in Josephson Junction Chains (1997)
Choi, Mahn-Soo, Yi, J., Choi, M. Y., Choi, J.
We investigate the quantum phase transition in a one-dimensional chain of ultra-small superconducting grains, considering both the self- and junction capacitances. At zero temperature, the system is...
Dissipative Dynamics of Quantum Vortices in Superconducting Arrays (1997)
Choi, Mahn-Soo, Lee, Sung-Ik, Choi, M. Y.
We consider a two-dimensional array of ultra-small superconducting grains, weakly coupled by Josephson junctions with large charging energy. We start from an effective action based on a microscopic...
The Effects of d_{x^2-y^2}-d_{xy} Mixing on Vortex Structures and Magnetization (1996)
The structure of an isolated single vortex and the vortex lattice, and the magnetization in a $d$-wave superconductor are investigated within a phenomenological Ginzburg-Landau (GL) model including...
Exact Calculation of the Vortex-Antivortex Interaction Energy in the Anisotropic 3D XY-model (1995)
We have developed an exact method to calculate the vortex-antivortex interaction energy in the anisotropic 3D-XY model. For this calculation, dual transformation which is already known for the 2D...