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

arXiv:1502.00998 · Physical Review A

Fast expansions and compressions of trapped-ion chains

Mikel Palmero, S. Martínez-Garaot, Joseba Alonso, Jonathan Home, Juan Gonzalo Muga

Published May 15, 2015• 19 citations
arXivHTMLPDF

Abstract

We investigate the dynamics under diabatic expansions or compressions of linear ion chains. Combining a dynamical normal-mode harmonic approximation with the invariant-based inverse-engineering technique, we design protocols that minimize the final motional excitation of the ions. This can substantially reduce the transition time between high and low trap-frequency operations, potentially contributing to the development of scalable quantum information processing.

DOI
10.1103/physreva.91.053411

Related papers

Fast transport of mixed-species ion chains within a Paul trap

Mikel Palmero, R. Bowler, John Gaebler +2 more

We investigate the dynamics of mixed-species ion crystals during transport between spatially distinct locations in a linear Paul trap in the diabatic regime. In a general mixed-species crystal, all degrees of freedom along the direction of transport are excited by an accelerating well, so unlike the case of same-species ions, where only the center-of-mass mode is excited, several degrees of freedom have to be simultaneously controlled by the transport protocol. We design protocols that lead to low final excitations in the diabatic regime using invariant-based inverse engineering for two different-species ions and also show how to extend this approach to longer mixed-species ion strings. Fast transport of mixed-species ion strings can significantly reduce the operation time in certain architectures for scalable quantum-information processing with trapped ions.

arXiv:1406.7455•Physical Review A•Nov 6, 2014•44 citations

Shortcuts to adiabatic rotation of a two-ion chain

Ander Tobalina, Juan Gonzalo Muga, Ion Lizuain +1 more

Abstract We inverse engineer fast rotations of a transversally tight, linear trap with two ions for a predetermined rotation angle and time, avoiding final excitation. Different approaches are analyzed and compared when the ions are of the same species or of different species. The separability into dynamical normal modes for equal ions in a harmonic trap, or for different ions in non-harmonic traps with up to quartic terms allows for simpler computations of the rotation protocols. For non-separable scenarios, in particular for different ions in harmonic traps, rotation protocols are also found using more costly numerical optimisations.

arXiv:2106.09293•Quantum Science and Technology•Aug 16, 2021•3 citations

Fast separation of two trapped ions

M Palmero, S. Martínez-Garaot, U G Poschinger +2 more

We design fast protocols to separate or recombine two ions in a segmented Paul trap. By inverse engineering the time evolution of the trapping potential composed of a harmonic and a quartic term, it is possible to perform these processes in a few microseconds without final excitation. These times are much shorter than the ones reported so far experimentally. The design is based on dynamical invariants and dynamical normal modes. Anharmonicities beyond the harmonic approximation at potential minima are taken into account perturbatively. The stability versus an unknown potential bias is also studied.

arXiv:1505.04942•New Journal of Physics•Sep 18, 2015•30 citations

Fast transitionless expansions of Gaussian anharmonic traps for cold atoms: Bang-singular-bang control

Xiao-Jing Lu, Xi Chen, Joseba Alonso +1 more

Combining invariant-based inverse engineering, perturbation theory, and optimal control theory, we design fast, transitionless expansions of cold neutral atoms or ions in Gaussian anharmonic traps. Bounding the possible trap frequencies and using a ``bang-singular-bang'' control we find fast processes for a continuum of durations up to a minimum time that corresponds to a purely bang-bang (stepwise frequency constant) control.

arXiv:1401.1352•Physical Review A•Feb 20, 2014•22 citations

Quantum invariant-based control of interacting trapped ions

Selwyn Simsek, Florian Mintert

Invariant-based inverse engineering is an elegant approach to quantum control with corresponding experimental implementations that perform tasks with applications in quantum information processing such as shuttling trapped ions. We build on recent work to generalise invariant-based inverse engineering to control two coupled harmonic oscillators in any number of spatial dimensions. This may be used to perform experimentally relevant tasks such as separation of trapped ions, which is demonstrated numerically, achieving transfer fidelities of over 96% as well as low motional number excitations.

arXiv:2112.13905•Dec 27, 2021•0 citations

Fast transitionless expansion of cold atoms in optical Gaussian-beam traps

E. Torrontegui, Xi Chen, Michele Modugno +3 more

We study fast expansions of cold atoms in a three-dimensional Gaussian-beam optical trap. Three different methods to avoid final motional excitation are compared: inverse engineering using Lewis-Riesenfeld invariants, which provides the best overall performance, a bang-bang approach, and a fast adiabatic approach. We analyze the excitation effect of anharmonic terms, radial-longitudinal coupling, and radial-frequency mismatch. In the inverse-engineering approach these perturbations can be suppressed or mitigated by increasing the laser beam waist.

arXiv:1111.0035•Physical Review A•Mar 5, 2012•75 citations
We investigate the dynamics under diabatic expansions or compressions of linear ion chains. Combining a dynamical normal-mode harmonic approximation with the invariant-based inverse-engineering technique, we design protocols that minimize the final motional excitation of the ions. This can substantially reduce the transition time between high and low trap-frequency operations, potentially contributing to the development of scalable quantum information processing.
We investigate the dynamics of mixed-species ion crystals during transport between spatially distinct locations in a linear Paul trap in the diabatic regime. In a general mixed-species crystal, all degrees of freedom along the direction of transport are excited by an accelerating well, so unlike the case of same-species ions, where only the center-of-mass mode is excited, several degrees of freedom have to be simultaneously controlled by the transport protocol. We design protocols that lead to low final excitations in the diabatic regime using invariant-based inverse engineering for two different-species ions and also show how to extend this approach to longer mixed-species ion strings. Fast transport of mixed-species ion strings can significantly reduce the operation time in certain architectures for scalable quantum-information processing with trapped ions.
Abstract We inverse engineer fast rotations of a transversally tight, linear trap with two ions for a predetermined rotation angle and time, avoiding final excitation. Different approaches are analyzed and compared when the ions are of the same species or of different species. The separability into dynamical normal modes for equal ions in a harmonic trap, or for different ions in non-harmonic traps with up to quartic terms allows for simpler computations of the rotation protocols. For non-separable scenarios, in particular for different ions in harmonic traps, rotation protocols are also found using more costly numerical optimisations.
We design fast protocols to separate or recombine two ions in a segmented Paul trap. By inverse engineering the time evolution of the trapping potential composed of a harmonic and a quartic term, it is possible to perform these processes in a few microseconds without final excitation. These times are much shorter than the ones reported so far experimentally. The design is based on dynamical invariants and dynamical normal modes. Anharmonicities beyond the harmonic approximation at potential minima are taken into account perturbatively. The stability versus an unknown potential bias is also studied.
Invariant-based inverse engineering is an elegant approach to quantum control with corresponding experimental implementations that perform tasks with applications in quantum information processing such as shuttling trapped ions. We build on recent work to generalise invariant-based inverse engineering to control two coupled harmonic oscillators in any number of spatial dimensions. This may be used to perform experimentally relevant tasks such as separation of trapped ions, which is demonstrated numerically, achieving transfer fidelities of over 96% as well as low motional number excitations.
We study fast expansions of cold atoms in a three-dimensional Gaussian-beam optical trap. Three different methods to avoid final motional excitation are compared: inverse engineering using Lewis-Riesenfeld invariants, which provides the best overall performance, a bang-bang approach, and a fast adiabatic approach. We analyze the excitation effect of anharmonic terms, radial-longitudinal coupling, and radial-frequency mismatch. In the inverse-engineering approach these perturbations can be suppressed or mitigated by increasing the laser beam waist.