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:1202.0408 · Physical Review A

Quantum processing by adiabatic transfer through a manifold of dark states

Santosh Kumar, Deepak Kumar

Published May 22, 2012• 9 citations
arXivHTMLPDF

Abstract

We consider a network whose nodes are electromagnetic cavities, each coupled to a single three-level atom. The nodes are connected by optical fibers. Each atom is addressed by a control laser, which along with the cavity field drives atomic transitions. The network can be in the form of chain or two- and three-dimensional arrays of $N$ cavities connected by ${N}_{B}$ fibers. Following the work on a two-cavity system by Pellizzari, we find that under certain conditions the system possesses two kinds of dark states. The first kind are $N$ states corresponding to atomic excitations at each node and these are our logical states for quantum processing. The second kind are ${N}_{B}$ degenerate dark states on pairs of sites connected by a fiber. By manipulating intensities and phases of control lasers on the cavities, one can pass adiabatically among these dark states due to their degeneracy. This network operates as an $N$-level quantum system in which one can generate computationally useful states by protocols of external controls. We obtain numerical results for small chains and lattices to demonstrate some quantum operations such as the transport of states across the array, generation of $W$ states, and Fourier-like states. We also discuss effects of dissipation and limitations of the model.

DOI
10.1103/physreva.85.052317

Related papers

Quantum processing through a manifold of dark states

Santosh Kumar, Deepak Kumar

We propose a scalable network, in which all quantum operations can be executed through external controls. Nodes of this network are high-finesse electromagnetic cavities, each coupled to a single three-level atom. The nodes are connected by optical fibers. Each atom is addressed by a control laser, which along with the cavity field drives atomic transitions. The network can be in the form of arrays of N-cavities connected by NB fibers in one to three dimensions. We find that under certain conditions, the system possesses two kinds of degenerate dark states. The first kind are N states corresponding to atomic excitations at each node and these are our logical states for quantum processing. The second kind are NB states on pairs of sites connected by a fibre. By manipulating intensities and phases of control lasers on the cavities, one can pass adiabatically among these dark states due to their degeneracy. This network operates as a N-level quantum system in which one can generate computationally useful states by protocols of external controls. We obtain numerical results for small chains and square lattices to demonstrate some quantum operations like the transport of states across the array, generation of superposed states and phase-flipping in a network. We also discuss effects of dissipation and limitations of the model.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 15, 2012•0 citations

Quantum state transfer between distant nodes of a quantum network via adiabatic passage

Yan‐Li Zhou, Yimin Wang, Long-Long Liang +1 more

A scheme is presented to realize transfer of a three-dimensional quantum state between two atoms trapped in distant cavities connected by an optical fiber, whose mode is resonant with the polarization cavity modes. Performing an adiabatic passage along dark states, the fiber mode remains in the vacuum state and the population of the cavities being excited can be negligible under certain conditions. In addition, atomic transitions in our scheme are largely detuned from cavity modes. As a consequence, the atomic spontaneous emission and the fiber decay can be effectively eliminated. Furthermore, we give some discussions about the fidelity of our scheme.

Physical Review A•Apr 29, 2009•47 citations

Quantum-state transfer between tripod atoms over a dark fiber

G. Bevilacqua, Ferruccio Renzoni

In this work we introduce a model for quantum-state transfer between tripod atoms over a dark fiber. Two tripod atoms are confined in separate cavities linked by an optical fiber. The cavities and the fiber sustain two optical modes of opposite circular polarization. For each atom, the two ground states encode the quantum state to be transferred and are coupled to a common excited state by the cavity modes of opposite polarization. The remaining transition for each atom is used to control the transfer process. We demonstrate that by using laser pulses the dynamics of the system can be confined within a degenerate dark state subspace, with the different dark states interacting via nonadiabatic couplings. We solve analytically the dynamics in the dark state subspace, and determine the conditions on the pulse shape for the implementation of the quantum transfer. We identify a possible pulse shape which satisfies the required conditions, and demonstrate the quantum-state transfer via numerical simulations.

Physical Review A•Sep 9, 2013•5 citations

Analysis of adiabatic transfer in cavity QED

Joyee Ghosh, Rupamanjari Ghosh, Deepak Kumar

A three-level atom in a $Λ$ configuration trapped in an optical cavity forms a basic unit in a number of proposed protocols for quantum information processing. Through control with an appropriate laser, this system allows for efficient storage of cavity photons into long-lived atomic excitations, and their retrieval with high fidelity. This process presumes an adiabatic transfer through the `dark state', a coherent superposition of the two lower levels of the $Λ$ system, by a slow variation of the intensity of the control laser. We study the full quantum mechanics of this transfer process with a view to examine the nonadiabatic effects, as the control laser is varied in time. The nonadiabatic effects arise due to inevitable excitations of the system to states involving the highest level of the $Λ$ configuration, which is radiative. We formulate the problem in terms of the instantaneous eigenstates and solve it numerically, allowing for spontaneous decays from the excited level. We present detailed results for both storage and retrieval for a suitable range of variation rates and intensity of the control laser, and examine optimum conditions for the transfer process.

arXiv:0907.1215•Jul 7, 2009•1 citation

Adiabatic quantum processing in an atom-cavity-fibre network through a manifold of dark states

Santosh Kumar, Deepak Kumar

Recently, we propose a scalable quantum network [Phys. Rev. A, 85 052317 (2012)], in which all quantum operations can be executed through external control lasers. This scheme has a drawback that the number of qubits are logN for a network of N nodes. We are perusing procedure which may circumvent this disadvantage.

•Dec 1, 2012•0 citations

State transfer and entanglement with atomic ensembles in a one-dimensional fibre-coupled cavity chain

Z J Deng, L-M Liang, J-M Chen +1 more

A simple scheme is presented to realize state transfer and entanglement with atomic ensembles in a one-dimensional fibre-coupled cavity chain. It is immune to atomic spontaneous emission, cavity decay and fibre decay by adiabatic dark state evolution. Moreover, with atomic-ensemble qubits instead of single-atom qubits, the process can be speeded up, which is important in view of decoherence. The most interesting aspect is that it can realize state transfer, the two-node maximum entanglement state between any selected two nodes and the m -node W state among any selected m nodes, which might be very useful in selective participation in distributed quantum information processing.

Journal of Physics B Atomic Molecular and Optical Physics•Mar 9, 2010•5 citations
We consider a network whose nodes are electromagnetic cavities, each coupled to a single three-level atom. The nodes are connected by optical fibers. Each atom is addressed by a control laser, which along with the cavity field drives atomic transitions. The network can be in the form of chain or two- and three-dimensional arrays of NNN cavities connected by NB{N}_{B}NB​ fibers. Following the work on a two-cavity system by Pellizzari, we find that under certain conditions the system possesses two kinds of dark states. The first kind are NNN states corresponding to atomic excitations at each node and these are our logical states for quantum processing. The second kind are NB{N}_{B}NB​ degenerate dark states on pairs of sites connected by a fiber. By manipulating intensities and phases of control lasers on the cavities, one can pass adiabatically among these dark states due to their degeneracy. This network operates as an NNN-level quantum system in which one can generate computationally useful states by protocols of external controls. We obtain numerical results for small chains and lattices to demonstrate some quantum operations such as the transport of states across the array, generation of WWW states, and Fourier-like states. We also discuss effects of dissipation and limitations of the model.
We propose a scalable network, in which all quantum operations can be executed through external controls. Nodes of this network are high-finesse electromagnetic cavities, each coupled to a single three-level atom. The nodes are connected by optical fibers. Each atom is addressed by a control laser, which along with the cavity field drives atomic transitions. The network can be in the form of arrays of N-cavities connected by NB fibers in one to three dimensions. We find that under certain conditions, the system possesses two kinds of degenerate dark states. The first kind are N states corresponding to atomic excitations at each node and these are our logical states for quantum processing. The second kind are NB states on pairs of sites connected by a fibre. By manipulating intensities and phases of control lasers on the cavities, one can pass adiabatically among these dark states due to their degeneracy. This network operates as a N-level quantum system in which one can generate computationally useful states by protocols of external controls. We obtain numerical results for small chains and square lattices to demonstrate some quantum operations like the transport of states across the array, generation of superposed states and phase-flipping in a network. We also discuss effects of dissipation and limitations of the model.
A scheme is presented to realize transfer of a three-dimensional quantum state between two atoms trapped in distant cavities connected by an optical fiber, whose mode is resonant with the polarization cavity modes. Performing an adiabatic passage along dark states, the fiber mode remains in the vacuum state and the population of the cavities being excited can be negligible under certain conditions. In addition, atomic transitions in our scheme are largely detuned from cavity modes. As a consequence, the atomic spontaneous emission and the fiber decay can be effectively eliminated. Furthermore, we give some discussions about the fidelity of our scheme.
In this work we introduce a model for quantum-state transfer between tripod atoms over a dark fiber. Two tripod atoms are confined in separate cavities linked by an optical fiber. The cavities and the fiber sustain two optical modes of opposite circular polarization. For each atom, the two ground states encode the quantum state to be transferred and are coupled to a common excited state by the cavity modes of opposite polarization. The remaining transition for each atom is used to control the transfer process. We demonstrate that by using laser pulses the dynamics of the system can be confined within a degenerate dark state subspace, with the different dark states interacting via nonadiabatic couplings. We solve analytically the dynamics in the dark state subspace, and determine the conditions on the pulse shape for the implementation of the quantum transfer. We identify a possible pulse shape which satisfies the required conditions, and demonstrate the quantum-state transfer via numerical simulations.
A three-level atom in a ΛΛΛ configuration trapped in an optical cavity forms a basic unit in a number of proposed protocols for quantum information processing. Through control with an appropriate laser, this system allows for efficient storage of cavity photons into long-lived atomic excitations, and their retrieval with high fidelity. This process presumes an adiabatic transfer through the `dark state', a coherent superposition of the two lower levels of the ΛΛΛ system, by a slow variation of the intensity of the control laser. We study the full quantum mechanics of this transfer process with a view to examine the nonadiabatic effects, as the control laser is varied in time. The nonadiabatic effects arise due to inevitable excitations of the system to states involving the highest level of the ΛΛΛ configuration, which is radiative. We formulate the problem in terms of the instantaneous eigenstates and solve it numerically, allowing for spontaneous decays from the excited level. We present detailed results for both storage and retrieval for a suitable range of variation rates and intensity of the control laser, and examine optimum conditions for the transfer process.
A simple scheme is presented to realize state transfer and entanglement with atomic ensembles in a one-dimensional fibre-coupled cavity chain. It is immune to atomic spontaneous emission, cavity decay and fibre decay by adiabatic dark state evolution. Moreover, with atomic-ensemble qubits instead of single-atom qubits, the process can be speeded up, which is important in view of decoherence. The most interesting aspect is that it can realize state transfer, the two-node maximum entanglement state between any selected two nodes and the m -node W state among any selected m nodes, which might be very useful in selective participation in distributed quantum information processing.