Subpicosecond 
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 rotations of atomic clock states

Song, Yunheung; Lee, Han-gyeol; Kim, Hyosub; Jo, Hanlae; Ahn, Jaewook

doi:10.1103/physreva.97.052322

Cited by 8 publications

(6 citation statements)

References 45 publications

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“…1(b) shows the time evolution pathways of |∓ driven by respective polarization components. After the cyclic evolution by the two pulses, |∓ states get geometric phases ±θ − π , respectively, corresponding to − 1 2 of the solid angle enclosed by the evolution pathways [5], while the dynamic phase φ d is due to the intensity-and detuning-dependent eigenenergy [19] and dynamic Stark shift from neighboring transitions [20]. Thus we get |ψ (t f ) = α−β √ 2 e iφ − |− + α+β √ 2 e iφ + | +, in which φ ∓ = ±θ − π + φ d are the phases gained during the time evolution (see the Appendix for more details).…”

Section: Theoretical Considerationmentioning

confidence: 99%

“…Qubit rotations about an arbitrary axisn = n xx + n yŷ can be implemented with an additional pair of time-delayed pulses. Since our scheme works in the regime where the hyperfine splitting is neglected, we adopt a method utilizing the hyperfine interaction in a longer timescale [20]. In the interaction picture where the qubit basis is |0 = |0 and |1 = e −iω hf t |1 , the Cartesian basis is given by |± = |0 ± e iω hf t |1 .…”

Section: Theoretical Considerationmentioning

confidence: 99%

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Berry-phase gates for fast and robust control of atomic clock states

Song

Lim

Ahn

2020

Phys. Rev. Research

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We propose and experimentally demonstrate a fast Berry-phase gate, which is implemented by picosecondtimescale optical pulses to make the qubit system of atomic clock states adiabatically evolve on a closed loop. The characteristic features of the proposed gate are gate speed and robustness against control fluctuations, which can potentially resolve the decoherence and reliability issues in quantum information processing, at the same time. The experiment is conducted with two linearly polarized, chirped optical pulses, interacting with five single rubidium atoms simultaneously in an array of optical tweezer dipole traps, to demonstrate the proposed picosecond-timescale clock-state gates. The robustness of the qubit rotation angle δ /δA = 1.5% is achieved with respect to the laser intensity (of pulse area A) fluctuation.

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Section: Theoretical Considerationmentioning

confidence: 99%

Section: Theoretical Considerationmentioning

confidence: 99%

Berry-phase gates for fast and robust control of atomic clock states

Song

Lim

Ahn

2020

Phys. Rev. Research

Self Cite

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“…This requires to operate on these systems orders of magnitude faster than the timescale set by the coupling to the environment. There is thus a continuous strive to better insulate qubits [1][2][3][4][5] and to design faster quantum operations [6][7][8][9]. Among the latter, a critical operation is the entanglement of two qubits, which requires a time lower-bounded by a speed limit t J = π/J set by a platform-dependent interaction strength J, e.g., proportional to a capacitance between two SC qubits [10].…”

Section: Introductionmentioning

confidence: 99%

Ultrafast energy exchange between two single Rydberg atoms on the nanosecond timescale

Chew,

Tomita,

Mahesh

et al. 2021

Preprint

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Rydberg atoms, with their giant electronic orbitals, exhibit dipole-dipole interaction reaching the GHz range at a distance of a micron, making them a prominent contender for realizing quantum operations well within their coherence time. However, such strong interactions have never been harnessed so far, mainly because of the stringent requirements on the fluctuation of the atom positions and the necessary excitation strength. Here, using atoms trapped in the motional groundstate of optical tweezers and excited to a Rydberg state with picosecond pulsed lasers, we observe an interaction-driven energy exchange, i.e., a Förster oscilation, occuring in a timescale of nanoseconds, two orders of magnitude faster than in any previous work with Rydberg atoms. This ultrafast coherent dynamics gives rise to a conditional phase which is the key resource for an ultrafast controlled-Z gate. This opens the path for quantum simulation and computation operating at the speed-limit set by dipole-dipole interactions with this ultrafast Rydberg platform.

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“…rogress in the field of quantum simulation and computation is fuelled by efforts made on a variety of platforms (for example, superconducting (SC) qubits, quantum dots, trapped ions, neutral atoms and so on) to reach a critical fidelity of quantum operations. This requires operation on these systems to be orders of magnitude faster than the timescale set by the coupling to the environment; thus, there are continuous attempts to better insulate qubits [1][2][3][4][5] and design faster quantum operations [6][7][8][9] . Among the latter, a critical operation is the entanglement of two qubits, which requires a time lower-bounded by a speed limit t J = π/J, set by a platform-dependent interaction strength J, which is, for example, proportional to a capacitance between two superconducting qubits 10 .…”

mentioning

confidence: 99%

Ultrafast energy exchange between two single Rydberg atoms on a nanosecond timescale

et al. 2022

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Rydberg atoms, with their enormous electronic orbitals, exhibit dipole–dipole interactions reaching the gigahertz range at a distance of a micrometre, making them a prominent contender for realizing ultrafast quantum operations. However, such strong interactions between two single atoms have so far never been harnessed due to the stringent requirements on the fluctuation of the atom positions and the necessary excitation strength. Here we introduce novel techniques to explore this regime. First, we trap and cool atoms to the motional quantum ground state of holographic optical tweezers, which allows control of the inter-atomic distance down to 1.5 μm with a quantum-limited precision of 30 nm. We then use ultrashort laser pulses to excite a pair of these nearby atoms to a Rydberg state simultaneously, far beyond the Rydberg blockade regime, and perform Ramsey interferometry with attosecond precision. This allows us to induce and track an ultrafast interaction-driven energy exchange completed on nanosecond timescales—two orders of magnitude faster than in any other Rydberg experiments in the tweezers platform so far. This ultrafast coherent dynamics gives rise to a conditional phase, which is the key resource for a quantum gate, opening the path for quantum simulation and computation operating at the speed limit set by dipole–dipole interactions with this ultrafast Rydberg platform.

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Subpicosecond X rotations of atomic clock states

Cited by 8 publications

References 45 publications

Berry-phase gates for fast and robust control of atomic clock states

Berry-phase gates for fast and robust control of atomic clock states

Ultrafast energy exchange between two single Rydberg atoms on the nanosecond timescale

Ultrafast energy exchange between two single Rydberg atoms on a nanosecond timescale

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