Dynamics of a spin qubit in an optical dipole trap

Gerasimov, L. V.; Yusupov, R. R.; Bobrov, I. B.; Shchepanovich, D.; Kovlakov, E. V.; Straupe, S. S.; Kulik, S. P.; Kupriyanov, D. V.

doi:10.1103/physreva.103.062426

Cited by 12 publications

(4 citation statements)

References 31 publications

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“…2. For dynamics of a single qubit the Rayleigh scattering preserves the atomic coherence, but the Raman scattering induces irreversible loss of coherence, see [29,30].…”

Section: Incoherent Lossesmentioning

confidence: 99%

Coupled dynamics of spin qubits in optical dipole microtraps

Герасимов¹,

Yusupov²,

Moiseevsky³

et al. 2022

Preprint

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Single atoms in dipole microtraps or optical tweezers have recently become a promising platform for quantum computing and simulation. Here we report a detailed theoretical analysis of the physics underlying an implementation of a Rydberg two-qubit gate in such a system -a cornerstone protocol in quantum computing with single atoms. We focus on a blockade-type entangling gate and consider various decoherence processes limiting its performance in a real system. We provide numerical estimates for the limits on fidelity of the maximally entangled states and predict the full process matrix corresponding to the noisy two-qubit gate. Our methods and results may find implementation in numerical models for simulation and optimization of neutral atom based quantum processors.

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“…2. For dynamics of a single qubit the Rayleigh scattering preserves the atomic coherence, but the Raman scattering induces irreversible loss of coherence, see [29,30].…”

Section: Incoherent Lossesmentioning

confidence: 99%

Coupled dynamics of spin qubits in optical dipole microtraps

Герасимов¹,

Yusupov²,

Moiseevsky³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

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“…where ρ is the density operator of the mixed spin state incorporating incoherent processes associated with finite The problem of blockade leakage may become critical if the condition Ω ≪ δ R is not fulfilled and here we mainly discuss the spatial variations of δ R which subsequently lead to spatial dependence of the gate fidelity. Hence, we omit the description of the calculation scheme we use to derive the density operator of the output state, which will be published elsewhere [23].…”

Section: A Fidelity Analysismentioning

confidence: 99%

Spatial dependence of fidelity for a two-qubit Rydberg-blockade quantum gate

Vybornyi¹,

Gerasimov²,

Kupriyanov³

et al. 2022

Preprint

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We study the spatial performance of the entangling gate proposed by H. Levine et al. (Phys. Rev. Lett. 123, 170503 (2019)). This gate is based on a Rydberg blockade technique and consists of just two global laser pulses which drive nearby atoms. We analyze the multilevel Zeeman structure of interacting 87 Rb Rydberg atoms and model two experimentally available excitation schemes using specific driving beams geometry and polarization. In particular, we estimate the blockade shift dependence on inter-atomic distance and angle with respect to the quantization axis. In addition, we show that using Rydberg d-states, in contrast to s-states, leads to a pronounced angular dependence of the blockade shift and gate fidelity.

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“…These single [4] and multi-pulse sequences [5][6][7][8] have already been used to extend coherence in various physical systems, ranging from spin ensembles [9], semiconductor quantum dots [10,11], nitrogen-vacancy centers in diamond [12,13], superconducting qubits [14], ensembles of ultracold atoms and ions [15][16][17] to the limit of single atoms and ions [18][19][20]. Consequently, many key characteristics and possible causes of qubit decoherence in ultracold atomic systems have already been discussed and explained in various experimental and theoretical works [21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Measuring the environment of a Cs qubit with dynamical decoupling sequences

Burgardt¹,

Jäger²,

Julian³

et al. 2023

J. Phys. B: At. Mol. Opt. Phys.

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We report the experimental implementation of dynamical decoupling on a small, non-interacting ensemble of up to 25 optically trapped, neutral Cs atoms. The qubit consists of the two magnetic-insensitive Cs clock states |F = 3,mF = 0⟩ and |F = 4,mF = 0⟩, which are coupled by microwave radiation. We observe a significant enhancement of the coherence time when employing Carr-Purcell-Meiboom-Gill (CPMG) dynamical decoupling. A CPMG sequence with ten refocusing pulses increases the coherence time of 16.2(9) ms by more than one order of magnitude to 178(2) ms. In addition, we make use of the filter function formalism and utilize the CPMG sequence to measure the background noise floor affecting the qubit coherence, finding a power-law noise spectrum 1/ω^α with α = 0.89(2). This finding is in very good agreement with an independent measurement of the noise in the intensity of the trapping laser. Moreover, the measured coherence evolutions also exhibit signatures of low-frequency noise originating at distinct frequencies. Our findings point toward noise spectroscopy of engineered atomic baths through single-atom dynamical decoupling in a system of individual Cs impurities immersed in an ultracold 87Rb bath.

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Dynamics of a spin qubit in an optical dipole trap

Cited by 12 publications

References 31 publications

Coupled dynamics of spin qubits in optical dipole microtraps

Coupled dynamics of spin qubits in optical dipole microtraps

Spatial dependence of fidelity for a two-qubit Rydberg-blockade quantum gate

Measuring the environment of a Cs qubit with dynamical decoupling sequences

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