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Autor Creffield, Charles E. |
Documentos disponibles escritos por este autor (46)
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We investigate the dynamics of two interacting electrons confined to a pair of coupled quantum dots driven by an external ac field. By numerically integrating the two-electron Schrödinger equation in time, we find that for certain values of the [...]![]()
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Hur, G. ; Creffield, Charles E. ; Jones, P.H. ; Monteiro, T. S. | American Physical Society | 2005-07Recently, cesium atoms in optical lattices subjected to cycles of unequally spaced pulses have been found to show interesting behavior: they represent an experimental demonstration of a Hamiltonian ratchet mechanism, and they show strong variabi[...]![]()
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A powerful method of manipulating the dynamics of quantum coherent particles is to control the phase of their tunneling. We consider a system of two electrons hopping on a quasi-one- dimensional lattice in the presence of a uniform magnetic fiel[...]![]()
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We study the behavior of ultracold bosonic atoms held in an optical lattice. We first show how a self-trapping transition can be induced in the system either by increasing the number of atoms occupying a lattice site or by raising the interactio[...]![]()
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We study the response of a Bose-Einstein condensate to an unbiased periodic driving potential. By controlling the space and time symmetries of the driving we show how a directed current can be induced, producing a coherent quantum ratchet. Weak [...]![]()
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We study the effect of a strong, oscillating driving field on the dynamics of ultracold boson held in an optical lattice. Modeling the system as a Bose-Hubbard model, we show how the driving field can be used to produce and maintain a coherent a[...]![]()
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We consider the dynamics of a quantum particle held in a lattice potential and subjected to a time-dependent spin-orbit coupling. Tilting the lattice causes the particle to perform Bloch oscillations, and by suitably changing the Rashba interact[...]![]()
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We examine the dynamics of ultracold atoms held in optical-lattice potentials. By controlling the switching of a periodic driving potential we show how a phase-induced renormalization of the intersite tunneling can be used to produce directed mo[...]![]()
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The dynamics of cold bosonic atoms held in an optical lattice can be profoundly modified by using a periodic driving potential to induce the quantum interference effect termed ”coherent destruction of tunneling”. In this way the entanglement and[...]![]()
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In the limit of low particle density, electrons confined to a quantum dot form strongly correlated states termed Wigner molecules, in which the Coulomb interaction causes the electrons to become highly localized in space. By using an effective m[...]![]()
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Bose-Einstein condensates subject to short pulses (kicks) from standing waves of light represent a nonlinear analog of the well-known chaos paradigm, the quantum kicked rotor. Previous studies of the onset of dynamical instability (i.e., expo[...]![]()
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Heimsoth, Martin ; Hochstuhl, D. ; Creffield, Charles E. ; Carr, L.D. ; Sols Lucía, Fernando | IOP Publishing | 2013-10-07We show that the orbital Josephson effect appears in a wide range of driven atomic Bose-Einstein condensed systems, including quantum ratchets, double wells and box potentials. We use three separate numerical methods: the Gross-Pitaevskii equati[...]![]()
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A quantum dot (QD) is a structure in which electrons can be confined to small length scales, comparable to their Fermi wavelength. A set of electrons held in such a structure is conceptually similar to a set of atomic electrons bound to a nucleu[...]![]()
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Creffield, Charles E. ; Sols Lucía, Fernando ; Ciampini, D. ; Morsch, O. ; Arimondo, E. | American Physical Society | 2014-01-27We study the nonequilibrium dynamics of cold atoms held in an optical lattice subjected to a periodic driving potential. The expansion of an initially confined atom cloud occurs in two phases: an initial quadratic expansion followed by a ballist[...]![]()
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The Riemann hypothesis, which states that the nontrivial zeros of the Riemann zeta function all lie on a certain line in the complex plane, is one of the most important unresolved problems in mathematics. We propose here an approach to finding a[...]![]()
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Creffield, Charles E. ; Kornilovitch, P. E. ; Klepfish, E. G. ; Pike, E. R. ; Sarkar, Sarben | IOP Publishing Ltd. | 1997-05-05A Quantum Monte Carlo calculation of dynamical spin susceptibility in the half-filled 2D Hubbard model is presented for temperature T = 0.2t and an intermediate on-site repulsion U = 4t. Using the singular value decomposition technique we succee[...]![]()
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We describe a method to generate a synthetic gauge potential for ultracold atoms held in an optical lattice. Our approach uses a time-periodic driving potential based on quickly alternating two Hamiltonians to engineer the appropriate Aharonov-B[...]![]()
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He, Ran ; Ai, Ming-Zhong ; Cui, Jin-Ming ; Huang, Yun-Feng ; Han, Yong-Jian ; Li, Chuan-Feng ; Tu, Tao ; Creffield, Charles E. ; Sierra, G. ; Guo, Guang-Can | Amercican Physical Society | 2020-04-20The Riemann hypothesis, one of the most important open problems in pure mathematics, implies the most profound secret of prime numbers. One of the most interesting approaches to solving this hypothesis is to connect the problem with the spectrum[...]![]()
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We investigate the dynamics of a Bose-Einstein condensate held in an optical lattice under the influence of a strong periodic driving potential. Studying the mean-field version of the Bose- Hubbard model reveals that the condensate becomes dynam[...]![]()
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Creffield, Charles E. ; Háusler, Wolfgang ; Jefferson, John H ; Sarkar, Sarben | American Physical Society | 1999-04-15The low-lying eigenstates of a system of two electrons confined within a two-dimensional quantum dot with a hard polygonal boundary are obtained by means of exact diagonalization. The transition from a weakly correlated charge distribution for s[...]![]()
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The quantum dynamics of atoms subjected to pairs of closely spaced delta kicks from optical potentials are shown to be quite different from the well-known paradigm of quantum chaos, the single delta-kick system. We find the unitary matrix has a [...]![]()
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We investigate the dynamics of two interacting electrons moving in a one-dimensional array of quantum dots under the influence of an ac field. We show that the system exhibits two distinct regimes of behavior, depending on the ratio of the stre[...]![]()
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The calculation of the Floquet quasi-energies of a system driven by a time-periodic field is an efficient way to understand its dynamics. In particular, the phenomenon of dynamical localization can be related to the presence of close approaches [...]![]()
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The controlled transfer of particles from one site of a spatial lattice to another is essential for many tasks in quantum information processing and quantum communication. In this work we study how to induce long-range transfer between the two e[...]![]()
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Creffield, Charles E. ; Jefferson, John H ; Sarkar,, Sarben ; Tipton, D. L. J. | American Physical Society | 2000-09-15The low-energy eigenstates of two interacting electrons in a square quantum dot in a magnetic field are determined by numerical diagonalization. In the strong correlation regime, the low-energy eigenstates show Aharonov-Bohm-type oscillations, w[...]![]()
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Valdez, Marc Andrew ; Shchedrin, Gavriil ; Heimsoth, Martin ; Creffield, Charles E. ; Sols Lucía, Fernando ; Carr, Lincoln D. | American Physical Society | 2018-06-05We uncover signatures of quantum chaos in the many-body dynamics of a Bose-Einstein condensate-based quantum ratchet in a toroidal trap. We propose measures including entanglement, condensate depletion, and spreading over a fixed basis in many-b[...]![]()
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The two-dimensional (2D) vortex lattice in the extreme type-II limit is studied by Monte Carlo simulation of the corresponding 2D Coulomb gas, with identical pins placed at sites coinciding with the zero-temperature triangular vortex lattice. At[...]![]()
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Sols Lucía, Fernando ; Heimsoth, M. ; Creffield, Charles E. ; Carr, L.D. | IOP publishing ltd | 2012-07-26In a system of ac-driven condensed bosons we study a new type of Josephson effect occurring between states sharing the same region of space and the same internal atom structure. We first develop a technique to calculate the long-time dynamics of[...]![]()
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A two-level system subjected to a high-frequency driving field can exhibit an effect termed "coherent destruction of tunneling", in which the tunneling of the system is suppressed at certain values of the frequency and strength of the field. Thi[...]![]()
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We investigate the effect of electron-phonon interaction on the phononic properties in the onedimensional half-filled Holstein model of spinless fermions. By means of determinantal Quantum Monte Carlo simulation we show that the behavior of the [...]![]()
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We propose a scheme for producing directed motion in a lattice system by applying a periodic driving potential. By controlling the dynamics by means of the effect known as coherent destruction of tunneling, we demonstrate a novel ratchetlike eff[...]![]()
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Bayat, Abolfazl ; Creffield, Charles E. ; Jefferson, John H ; Pepper, Michael ; Bose, Sougato | IOP publishing ltd | 2015-10We show how single quantum dots, each hosting a singlet-triplet qubit, can be placed in arrays to build a spin quantum cellular automaton. A fast (? 10 ns) deterministic coherent singlet- triplet filtering, as opposed to current incoherent tunne[...]![]()
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Di Liberto, M. ; Creffield, Charles E. ; Japaridze, G. Y. ; Smith, C.Morais | American Physical Society | 2014-01-27By using a modulated magnetic field in a Feshbach resonance for ultracold fermionic atoms in optical lattices, we show that it is possible to engineer a class of models usually referred to as correlated-hopping models. These models differ from t[...]![]()
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Creffield, Charles E. ; Pieplow, G. ; Sols Lucía, Fernando ; Goldman, N. | IOP Publishing | 2016-09-06Shaking a lattice system, by modulating the location of its sites periodically in time, is a powerful method to create effective magnetic fields in engineered quantum systems, such as cold gases trapped in optical lattices. However, such schemes[...]![]()
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We study the dynamics of an Airy wave packet moving in a one-dimensional lattice potential. In contrast to the usual case of propagation in a continuum, for which such a wave packet experiences a uniform acceleration, the lattice bounds its velo[...]![]()
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Spectral weight function for the half-filled hubbard-model - a singular-value decomposition approach
Creffield, Charles E. ; Klepfish,, E.G. ; Pike, E. R. ; Sarkar, Sarben | American Physical Society | 1995-07-17The singular value decomposition technique is used to reconstruct the electronic spectral weight function for a half-filled Hubbard model with on-site repulsion U = 4t from quantum Monte Carlo data. A two-band structure for the single-particle e[...]![]()
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Creffield, Charles E. ; Klepfish, E. G. ; Pike, E. R. ; Sarkar, Sarben | American Physical Society | 1995-07-17The singular value decomposition technique is used to reconstruct the electronic spectral weight function for a half-filled Hubbard model with on-site repulsion U = 4t from quantum Monte Carlo data. A two-band structure for the single-particle e[...]![]()
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Garcia Coello, José ; Bayat, Abolfazl ; Bose, Sougato ; Jefferson, John H ; Creffield, Charles E. | American Physical Society | 2010-08-17We exploit the nondissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. [...]![]()
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We analyze the dynamics of two strongly interacting fermions moving in two-dimensional lattices under the action of a periodic electric field, both with and without a magnetic flux. Due to the interaction, these particles bind together forming a[...]![]()
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We examine the quantum dynamics of cold atoms subjected to pairs of closely spaced kicks from standing waves of light and find behavior quite unlike the well-studied quantum kicked rotor QKR. We show that the quantum phase space has a periodi[...]![]()
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The latest advances in the field of photonics have enabled the simulation of an increasing number of quantum models in photonic systems, turning them into an important tool for realizing exotic quantum phenomena. In this paper, different ways in[...]![]()
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We study the time-dependent dynamics of a Bose-Einstein condensate trapped in an optical lattice. Modeling the system as a Bose-Hubbard model, we show how applying a periodic driving field can induce coherent destruction of tunneling. In the low[...]![]()
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Heimsoth, M. ; Creffield, Charles E. ; Sols Lucía, Fernando | American Physical Society | 2010-08-12We present an analytical study of the response of cold atoms in an optical lattice to a weak time- and space-asymmetric periodic driving signal. In the noninteracting limit, and for a finite set of resonant frequencies, we show how a coherent, l[...]