Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Optics B Quantum and Semiclassical Optics

Quantum transport in magneto-optical double-potential wells

Ivan Deutsch, Paul M. Alsing, J. Grondalski, Shohini Ghose, D. L. Haycock, Poul Jessen

Published Oct 1, 2000• 22 citations
Publisher

Abstract

We review the quantum transport of ultra-cold alkali atoms trapped in a one-dimensional optical lattice of double-potential wells, engineered through a combination of ac-Stark shifts and Zeeman interactions. The system is modelled numerically through analysis of the bandstructure and integration of the time-dependent Schrödinger equation. By these means we simulate coherent control of the atomic wavepackets. We present results from ongoing experiments on laser-cooled caesium, including the demonstration of quantum state preparation and preliminary evidence for coherent tunnelling. Entanglement between the internal and motional degrees of freedom allows us to access the tunnelling dynamics by Stern-Gerlach measurements of the ground state magnetic populations. A scheme to extend this into a full reconstruction of the density matrix for the ground state angular momentum is presented. We further consider the classical dynamics of our system, which displays deterministic chaos. This has important implications for the distinction between classical and quantum mechanical transport.

DOI
10.1088/1464-4266/2/5/311

Related papers

Coherent quantum tunnelling and macroscopic superposition states in optical lattices

Ivan Deutsch, Poul Jessen

Summary form only given. The AC-Stark shift of a set of interfering laser beams together with the Zeeman interaction with external magnetic fields provide flexible mechanisms for coherently controlling atomic wave packets. When detuned far from atomic resonance, these optical lattices can trap cold atoms with minimal dissipation and thus provide an ideal environment for observing quantum coherent phenomena. We consider a one dimensional lattice of double wells produced by counterpropagating linearly polarized laser beams and a static magnetic field transverse to the laser wave vectors.

Conference on Lasers and Electro-Optics•Nov 27, 2002•0 citations

Quantum tunneling and coherent wavepacket dynamics in an optical lattice

D. L. Haycock

This dissertation reports on the experimental study of coherent wavepacket dynamics of cesium atoms in the double-well potentials of a one-dimensional, far-off-resonance optical lattice. An optical lattice is the periodic potential produced by the light shift interaction of an atom with the light field of interfering laser beams. With the proper choice of laser parameters and external magnetic fields, an array of double-well potentials is created. Using the techniques of laser cooling, atoms are trapped in the lattice and are prepared in a pure state through a combination of enhanced laser cooling in a near-resonance lattice and state selection in an accelerated far-off-resonance lattice. The atoms are prepared on one side of the double-well potential, and the atomic wavepackets will then oscillate between the left and right localized states of the double-well potential. Entanglement between the internal and external degrees of freedom makes it possible to follow the center-of-mass motion of the atoms by measuring the ground state magnetic populations via Stern-Gerlach analysis. The coherent dynamics of these wavepackets was studied under various combinations of lattice parameters such as lattice depth, applied transverse and longitudinal magnetic fields. There is excellent agreement between the experimentally measured oscillation frequencies and those predicted from a numerical analysis of the bandstructure of the lattice. For certain lattice parameters the total energy of the atom is below the potential barrier and the coherent motion corresponds to tunneling through a classically forbidden barrier. At specific times during the oscillation the atomic wavepacket corresponds to a coherent superposition of the mesoscopically distinct left and right localized states.

•Jan 1, 2000•1 citation

Quantum And Classical Dynamics Of Atoms In A Magneto-optical Lattice

Shohini Ghose

The transport of ultra‐cold atoms in magneto‐optical potentials provides a clean setting in which to investigate the distinct predictions of classical versus quantum dynamics for a system with coupled degrees of freedom. In this system, entanglement at the quantum level and chaos at the classical level arise from the coupling between the atomic spin and its center‐of‐mass motion. Experiments, performed deep in the quantum regime, correspond to dynamic quantum tunneling. This nonclassical behavior is contrasted with the predictions for an initial phase space distribution produced in the experiment, but undergoing classical Hamiltonian flow. We study conditions under which the trapped atoms can be made to exhibit classical dynamics through the process of continuous measurement, which localizes the probability distribution to phase space trajectories, consistent with the uncertainty principle and quantum “back‐action” noise. This method allows us to analytically and numerically identify the quantum‐classical boundary.

arXiv:quant-ph/0210131•AIP conference proceedings•Jan 1, 2003•0 citations

Atomic motion in magneto-optical double-well potentials: A testing ground for quantum chaos

Shohini Ghose, Paul M. Alsing, Ivan Deutsch

We have identified ultracold atoms in magneto-optical double-well potentials as a very clean setting in which to study the quantum and classical dynamics of a nonlinear system with multiple degrees of freedom. In this system, entanglement at the quantum level and chaos at the classical level arise from nonseparable couplings between the atomic spin and its center of mass motion. The main features of the chaotic dynamics are analyzed using action-angle variables and Poincaré surfaces of section. We show that for the initial state prepared in current experiments [D. J. Haycock et al., Phys. Rev. Lett. 85, 3365 (2000)], classical and quantum expectation values diverge after a finite time, and the observed experimental dynamics is consistent with quantum-mechanical predictions. Furthermore, the motion corresponds to tunneling through a dynamical potential barrier. The coupling between the spin and the motional subsystems, which are very different in nature from one another, leads to interesting questions regarding the transition from regular quantum dynamics to chaotic classical motion.

arXiv:quant-ph/0102085•Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics•Oct 24, 2001•17 citations

Chaotic dynamics and tunneling of an atom in a magneto-optical double-potential well

Shohini Ghose, Paul M. Alsing, Ivan Deutsch

Summary form only given. Dynamics associated with a particle in a double-potential well play a key role in numerous areas of pure and applied sciences, and is an important paradigm for quantum coherent evolution. Most fundamental is the decay or oscillation of a meta-stable state via quantum tunneling. We consider the dynamics of laser cooled atoms in a magneto-optical lattice of such double wells.

Quantum Electronics and Laser Science Conference•May 7, 2000•0 citations

Coherent Atom Transport via Enhanced Shortcuts to Adiabaticity: Double-Well Optical Lattice

Sascha H. Hauck, Vladimir M. Stojanović

Theoretical studies of coherent atom transport have as yet mainly been restricted to one-dimensional model systems with harmonic trapping potentials. Here we investigate this important phenomenon---a prerequisite for a variety of quantum-technology applications based on cold neutral atoms---under much more complex physical circumstances. More specifically yet, we study fast atomic transport in a moving double-well optical lattice, whose three-dimensional (anharmonic) potential is nonseparable in the $x$-$y$ plane. We first propose specific configurations of acousto-optic modulators that give rise to the moving-lattice effect in an arbitrary direction in this plane. We then determine moving-lattice trajectories that enable single-atom transport using two classes of quantum-control methods: shortcuts to adiabaticity (STA), here utilized in the form of inverse engineering based on a quadratic-in-momentum dynamical invariant of Lewis-Riesenfeld type, and their recently proposed modification termed enhanced STA (eSTA). Subsequently, we quantify the resulting single-atom dynamics by numerically solving the relevant time-dependent Schr\"odinger equations and compare the efficiency of STA- and eSTA-based transport by evaluating the respective fidelities. We show that---except for the regime of shallow lattices---the eSTA method consistently outperforms its STA counterpart. This study has direct implications for neutral-atom quantum computing based on collisional entangling two-qubit gates and quantum sensing of constant homogeneous forces via guided-atom interferometry.

arXiv:2112.14039•Physical Review Applied•Jul 8, 2022•13 citations
We review the quantum transport of ultra-cold alkali atoms trapped in a one-dimensional optical lattice of double-potential wells, engineered through a combination of ac-Stark shifts and Zeeman interactions. The system is modelled numerically through analysis of the bandstructure and integration of the time-dependent Schrödinger equation. By these means we simulate coherent control of the atomic wavepackets. We present results from ongoing experiments on laser-cooled caesium, including the demonstration of quantum state preparation and preliminary evidence for coherent tunnelling. Entanglement between the internal and motional degrees of freedom allows us to access the tunnelling dynamics by Stern-Gerlach measurements of the ground state magnetic populations. A scheme to extend this into a full reconstruction of the density matrix for the ground state angular momentum is presented. We further consider the classical dynamics of our system, which displays deterministic chaos. This has important implications for the distinction between classical and quantum mechanical transport.
Summary form only given. The AC-Stark shift of a set of interfering laser beams together with the Zeeman interaction with external magnetic fields provide flexible mechanisms for coherently controlling atomic wave packets. When detuned far from atomic resonance, these optical lattices can trap cold atoms with minimal dissipation and thus provide an ideal environment for observing quantum coherent phenomena. We consider a one dimensional lattice of double wells produced by counterpropagating linearly polarized laser beams and a static magnetic field transverse to the laser wave vectors.
This dissertation reports on the experimental study of coherent wavepacket dynamics of cesium atoms in the double-well potentials of a one-dimensional, far-off-resonance optical lattice. An optical lattice is the periodic potential produced by the light shift interaction of an atom with the light field of interfering laser beams. With the proper choice of laser parameters and external magnetic fields, an array of double-well potentials is created. Using the techniques of laser cooling, atoms are trapped in the lattice and are prepared in a pure state through a combination of enhanced laser cooling in a near-resonance lattice and state selection in an accelerated far-off-resonance lattice. The atoms are prepared on one side of the double-well potential, and the atomic wavepackets will then oscillate between the left and right localized states of the double-well potential. Entanglement between the internal and external degrees of freedom makes it possible to follow the center-of-mass motion of the atoms by measuring the ground state magnetic populations via Stern-Gerlach analysis. The coherent dynamics of these wavepackets was studied under various combinations of lattice parameters such as lattice depth, applied transverse and longitudinal magnetic fields. There is excellent agreement between the experimentally measured oscillation frequencies and those predicted from a numerical analysis of the bandstructure of the lattice. For certain lattice parameters the total energy of the atom is below the potential barrier and the coherent motion corresponds to tunneling through a classically forbidden barrier. At specific times during the oscillation the atomic wavepacket corresponds to a coherent superposition of the mesoscopically distinct left and right localized states.
The transport of ultra‐cold atoms in magneto‐optical potentials provides a clean setting in which to investigate the distinct predictions of classical versus quantum dynamics for a system with coupled degrees of freedom. In this system, entanglement at the quantum level and chaos at the classical level arise from the coupling between the atomic spin and its center‐of‐mass motion. Experiments, performed deep in the quantum regime, correspond to dynamic quantum tunneling. This nonclassical behavior is contrasted with the predictions for an initial phase space distribution produced in the experiment, but undergoing classical Hamiltonian flow. We study conditions under which the trapped atoms can be made to exhibit classical dynamics through the process of continuous measurement, which localizes the probability distribution to phase space trajectories, consistent with the uncertainty principle and quantum “back‐action” noise. This method allows us to analytically and numerically identify the quantum‐classical boundary.
We have identified ultracold atoms in magneto-optical double-well potentials as a very clean setting in which to study the quantum and classical dynamics of a nonlinear system with multiple degrees of freedom. In this system, entanglement at the quantum level and chaos at the classical level arise from nonseparable couplings between the atomic spin and its center of mass motion. The main features of the chaotic dynamics are analyzed using action-angle variables and Poincaré surfaces of section. We show that for the initial state prepared in current experiments [D. J. Haycock et al., Phys. Rev. Lett. 85, 3365 (2000)], classical and quantum expectation values diverge after a finite time, and the observed experimental dynamics is consistent with quantum-mechanical predictions. Furthermore, the motion corresponds to tunneling through a dynamical potential barrier. The coupling between the spin and the motional subsystems, which are very different in nature from one another, leads to interesting questions regarding the transition from regular quantum dynamics to chaotic classical motion.
Theoretical studies of coherent atom transport have as yet mainly been restricted to one-dimensional model systems with harmonic trapping potentials. Here we investigate this important phenomenon---a prerequisite for a variety of quantum-technology applications based on cold neutral atoms---under much more complex physical circumstances. More specifically yet, we study fast atomic transport in a moving double-well optical lattice, whose three-dimensional (anharmonic) potential is nonseparable in the xxx-yyy plane. We first propose specific configurations of acousto-optic modulators that give rise to the moving-lattice effect in an arbitrary direction in this plane. We then determine moving-lattice trajectories that enable single-atom transport using two classes of quantum-control methods: shortcuts to adiabaticity (STA), here utilized in the form of inverse engineering based on a quadratic-in-momentum dynamical invariant of Lewis-Riesenfeld type, and their recently proposed modification termed enhanced STA (eSTA). Subsequently, we quantify the resulting single-atom dynamics by numerically solving the relevant time-dependent Schr\"odinger equations and compare the efficiency of STA- and eSTA-based transport by evaluating the respective fidelities. We show that---except for the regime of shallow lattices---the eSTA method consistently outperforms its STA counterpart. This study has direct implications for neutral-atom quantum computing based on collisional entangling two-qubit gates and quantum sensing of constant homogeneous forces via guided-atom interferometry.