Scalable architecture for Atomtronics flux qubits

Through a combination of laser beams, we engineer a two-dimensional optical lattice of Mexican hat potentials able to host atoms in its ring-shaped wells. When tunneling can be ignored (at high laser intensities), we show that a well-defined qubit can be associated with the states of the atoms trapped in each of the rings. Each of these two-level systems can be manipulated by a suitable configuration of Raman laser beams imprinting a synthetic flux onto each Mexican hat cell of the lattice. Overall, we believe that the system has the potential to form a scalable architecture for atomtronic flux qubits.Through a combination of laser beams, we engineer a two-dimensional optical lattice of Mexican hat potentials able to host atoms in its ring-shaped wells. When tunneling can be ignored (at high laser intensities), we show that a well-defined qubit can be associated with the states of the atoms trapped in each of the rings. Each of these two-level systems can be manipulated by a suitable configuration of Raman laser beams imprinting a synthetic flux onto each Mexican hat cell of the lattice. Overall, we believe that the system has the potential to form a scalable architecture for atomtronic flux qubits.

arXiv:1606.06890Physical Review AApr 5, 20188 citations

Superfluid qubit systems with ring shaped optical lattices

Luigi Amico A, Davit Aghamalyan, Filip Auksztol +3 more

We study an experimentally feasible qubit system employing neutral atomic currents. Our system is based on bosonic cold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimensional and it provides the infrastructure to realize a tunable ring-ring interaction. Our implementation combines the low decoherence rates of neutral cold atoms systems, overcoming single site addressing, with the robustness of topologically protected solid state Josephson flux qubits. Characteristic fluctuations in the magnetic fields affecting Josephson junction based flux qubits are expected to be minimized employing neutral atoms as flux carriers. By breaking the Galilean invariance we demonstrate how atomic currents through the lattice provide an implementation of a qubit. This is realized either by artificially creating a phase slip in a single ring, or by tunnel coupling of two homogeneous ring lattices. The single qubit infrastructure is experimentally investigated with tailored optical potentials. Indeed, we have experimentally realized scaled ring-lattice potentials that could host, in principle, n ~ 10 of such ring-qubits, arranged in a stack configuration, along the laser beam propagation axis. An experimentally viable scheme of the two-ring-qubit is discussed, as well. Based on our analysis, we provide protocols to initialize, address, and read-out the qubit.We study an experimentally feasible qubit system employing neutral atomic currents. Our system is based on bosonic cold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimensional and it provides the infrastructure to realize a tunable ring-ring interaction. Our implementation combines the low decoherence rates of neutral cold atoms systems, overcoming single site addressing, with the robustness of topologically protected solid state Josephson flux qubits. Characteristic fluctuations in the magnetic fields affecting Josephson junction based flux qubits are expected to be minimized employing neutral atoms as flux carriers. By breaking the Galilean invariance we demonstrate how atomic currents through the lattice provide an implementation of a qubit. This is realized either by artificially creating a phase slip in a single ring, or by tunnel coupling of two homogeneous ring lattices. The single qubit infrastructure is experimentally investigated with tailored optical potentials. Indeed, we have experimentally realized scaled ring-lattice potentials that could host, in principle, n ~ 10 of such ring-qubits, arranged in a stack configuration, along the laser beam propagation axis. An experimentally viable scheme of the two-ring-qubit is discussed, as well. Based on our analysis, we provide protocols to initialize, address, and read-out the qubit.

arXiv:1304.4615Scientific ReportsMar 6, 2014135 citations

Atomtronic superconducting quantum interference device in synthetic dimensions

Wenxi Lai, Yu-Quan Ma, Yi-Wen Wei

Coherence and scalability are essential properties of quantum systems required in quantum computers. This study presents a high coherent and scalable qubit system with atomtronics in synthetic dimensions. It is atomtronic counterpart of superconducting quantum interference device. Comparing with traditional superconducting quantum interference device which requires at least $2$ -dimensional circuits, the synthetic dimensional superconducting quantum interference device can be realized only in $1$ -dimensional circuits. The synthetic dimensional system is composed of Bose-Einstein condensate in two neighboring optical wells which is coupled to an external coherent light. Control parameter for the qubit is naturally provided by artificial magnetic flux originated from the coherent atom-light coupling. It should be a great advantage for the scalability and integration feature of quantum logic gates.Coherence and scalability are essential properties of quantum systems required in quantum computers. This study presents a high coherent and scalable qubit system with atomtronics in synthetic dimensions. It is atomtronic counterpart of superconducting quantum interference device. Comparing with traditional superconducting quantum interference device which requires at least $2$-dimensional circuits, the synthetic dimensional superconducting quantum interference device can be realized only in $1$-dimensional circuits. The synthetic dimensional system is composed of Bose-Einstein condensate in two neighboring optical wells which is coupled to an external coherent light. Control parameter for the qubit is naturally provided by artificial magnetic flux originated from the coherent atom-light coupling. It should be a great advantage for the scalability and integration feature of quantum logic gates.

arXiv:2303.01655Mar 3, 20230 citations

Quantum computing with atomic Josephson junction arrays

Lin Tian, P. Zoller

We present a quantum computing scheme with atomic Josephson junction arrays. The system consists of a small number of atoms with three internal states and trapped in a far-off-resonant optical lattice. Raman lasers provide the ``Josephson'' tunneling, and the collision interaction between atoms represent the ``capacitive'' couplings between the modes. The qubit states are collective states of the atoms with opposite persistent currents. This system is closely analogous to the superconducting flux qubit. Single-qubit quantum logic gates are performed by modulating the Raman couplings, while two-qubit gates result from a tunnel coupling between neighboring wells. Readout is achieved by tuning the Raman coupling adiabatically between the Josephson regime to the Rabi regime, followed by a detection of atoms in internal electronic states. Decoherence mechanisms are studied in detail promising a high ratio between the decoherence time and the gate operation time.We present a quantum computing scheme with atomic Josephson junction arrays. The system consists of a small number of atoms with three internal states and trapped in a far-off-resonant optical lattice. Raman lasers provide the ``Josephson'' tunneling, and the collision interaction between atoms represent the ``capacitive'' couplings between the modes. The qubit states are collective states of the atoms with opposite persistent currents. This system is closely analogous to the superconducting flux qubit. Single-qubit quantum logic gates are performed by modulating the Raman couplings, while two-qubit gates result from a tunnel coupling between neighboring wells. Readout is achieved by tuning the Raman coupling adiabatically between the Josephson regime to the Rabi regime, followed by a detection of atoms in internal electronic states. Decoherence mechanisms are studied in detail promising a high ratio between the decoherence time and the gate operation time.

arXiv:quant-ph/0306085Physical Review AOct 20, 200340 citations

Flux qubits with neutral currents in optical lattices

Luigi Amico A, Davit Aghamalyan, Herbert Crepaz +3 more

Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 andNational Institute of Education and Institute of Advanced Studies,Nanyang Technological University, 1 Nanyang Walk, Singapore 637616(Dated: January 11, 2014)We study an experimentally feasible qubit system employing neutral currents. Our system is based on bosoniccold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimen-sional and it provides the infrastructure to realize a tunable ring-ring interaction. By breaking the Galileaninvariance we demonstrate how atomic currents through the lattice provide a realization of a qubit. We breakthe Galilean invariance either by artiﬁcially creating a phase slip in a single ring, or by considering two ho-mogeneous ring lattices, coupled by tunneling interaction. The Hamiltonian of the system effectively leads toa washboard potential in the phase representation, tilted by the applied ’ﬂux’. The single qubit infrastructureis experimentally investigated with tailored optical potentials. An experimentally feasible scheme of the two-ring-qubit is discussed. In this case, the dynamics is demonstrated to show macroscopic quantum self trapping.Time-of-ﬂight expansion maps the pattern of atomic currents into detectable atomic density distributions. Basedon our analysis, we provide viable protocols to initialize, address, and read-out the qubit.Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 andNational Institute of Education and Institute of Advanced Studies,Nanyang Technological University, 1 Nanyang Walk, Singapore 637616(Dated: January 11, 2014)We study an experimentally feasible qubit system employing neutral currents. Our system is based on bosoniccold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimen-sional and it provides the infrastructure to realize a tunable ring-ring interaction. By breaking the Galileaninvariance we demonstrate how atomic currents through the lattice provide a realization of a qubit. We breakthe Galilean invariance either by artiﬁcially creating a phase slip in a single ring, or by considering two ho-mogeneous ring lattices, coupled by tunneling interaction. The Hamiltonian of the system effectively leads toa washboard potential in the phase representation, tilted by the applied ’ﬂux’. The single qubit infrastructureis experimentally investigated with tailored optical potentials. An experimentally feasible scheme of the two-ring-qubit is discussed. In this case, the dynamics is demonstrated to show macroscopic quantum self trapping.Time-of-ﬂight expansion maps the pattern of atomic currents into detectable atomic density distributions. Basedon our analysis, we provide viable protocols to initialize, address, and read-out the qubit.

Apr 16, 20130 citations

Addressed qubit manipulation in radio-frequency dressed lattices

G. Sinuco-León, B. M. Garraway

Precise control over qubits encoded as internal states of ultracold atoms in arrays of potential wells is a key element for atomtronics applications in quantum information, quantum simulation and atomic microscopy. Here we theoretically study atoms trapped in an array of radio-frequency dressed potential wells and propose a scheme for engineering fast and high-fidelity single-qubit gates with low error due to cross-talk. In this proposal, atom trapping and qubit manipulation relies exclusively on long-wave radiation making it suitable for atom-chip technology. We demonstrate that selective qubit addressing with resonant microwaves can be programmed by controlling static and radio-frequency currents in microfabricated conductors. These results should enable studies of neutral-atom quantum computing architectures, powered by low-frequency electromagnetic fields with the benefit of simple schemes for controlling individual qubits in large ensembles.Precise control over qubits encoded as internal states of ultracold atoms in arrays of potential wells is a key element for atomtronics applications in quantum information, quantum simulation and atomic microscopy. Here we theoretically study atoms trapped in an array of radio-frequency dressed potential wells and propose a scheme for engineering fast and high-fidelity single-qubit gates with low error due to cross-talk. In this proposal, atom trapping and qubit manipulation relies exclusively on long-wave radiation making it suitable for atom-chip technology. We demonstrate that selective qubit addressing with resonant microwaves can be programmed by controlling static and radio-frequency currents in microfabricated conductors. These results should enable studies of neutral-atom quantum computing architectures, powered by low-frequency electromagnetic fields with the benefit of simple schemes for controlling individual qubits in large ensembles.

New Journal of PhysicsMar 10, 201610 citations

2

-dimensional circuits, the synthetic dimensional superconducting quantum interference device can be realized only in

1

-dimensional circuits. The synthetic dimensional system is composed of Bose-Einstein condensate in two neighboring optical wells which is coupled to an external coherent light. Control parameter for the qubit is naturally provided by artificial magnetic flux originated from the coherent atom-light coupling. It should be a great advantage for the scalability and integration feature of quantum logic gates.