Experimental Uhrig dynamical decoupling using trapped ions

Biercuk, Michael J.; Uys, Hermann; VanDevender, Aaron P.; Shiga, Nobuyasu; Itano, Wayne M.; Bollinger, John J.

doi:10.1103/physreva.79.062324

Cited by 120 publications

(187 citation statements)

References 37 publications

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“…Recently, a method to incorporate shaped pulses of finite amplitude into UDD paves the way of realistic experiments [20]. UDD was first verified in experiments by microwave control of trapped ions in various artificial classical noises [21][22][23], and then UDD against realistic quantum noises was realized for radical electron spins in irradiated malonic acid crystals [24].…”

Section: Introductionmentioning

confidence: 99%

Protection of quantum systems by nested dynamical decoupling

Wang

Liu

2011

Phys. Rev. A

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Based on a theorem we establish on dynamical decoupling of time-dependent systems, we present a scheme of nested Uhrig dynamical decoupling (NUDD) to protect multi-qubit systems in generic quantum baths to arbitrary decoupling orders, using only single-qubit operations. The number of control pulses in NUDD increases polynomially with the decoupling order. For general multi-level systems, this scheme can preserve a set of unitary Hermitian system operators which mutually either commute or anti-commute, and hence all operators in the Lie algebra generated from this set of operators, generating an effective symmetry group for the system up to a given order of precision. NUDD can be implemented with pulses of finite amplitude, up to an error in the second order of the pulse durations.

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Section: Introductionmentioning

confidence: 99%

Protection of quantum systems by nested dynamical decoupling

Wang

Liu

2011

Phys. Rev. A

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“…In addition to its high-order suppression of decoherence (at least in theory), UDD for singlequbit decoherence suppression could be powerful because it works for most general system-bath coupling [10], for a bath that has unknown spectral density (but with a sharp cut-off), and for time-dependent system-bath Hamiltonians as well [15]. Experimental studies of UDD under two specific situations have been reported [16][17][18]. For a recent concise review on UDD-related theoretical studies, see Ref.…”

Section: Introductionmentioning

confidence: 99%

Protecting unknown two-qubit entangled states by nesting Uhrig’s dynamical decoupling sequences

et al. 2010

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Future quantum technologies rely heavily on good protection of quantum entanglement against environment-induced decoherence. A recent study showed that an extension of Uhrig's dynamical decoupling (UDD) sequence can (in theory) lock an arbitrary but known two-qubit entangled state to the N th order using a sequence of N control pulses [Mukhtar et al., Phys. Rev. A 81, 012331 (2010)]. By nesting three layers of explicitly constructed UDD sequences, here we first consider the protection of unknown two-qubit states as superposition of two known basis states, without making assumptions of the system-environment coupling. It is found that the obtained decoherence suppression can be highly sensitive to the ordering of the three UDD layers and can be remarkably effective with the correct ordering. The detailed theoretical results are useful for general understanding of the nature of controlled quantum dynamics under nested UDD. As an extension of our three-layer UDD, it is finally pointed out that a completely unknown two-qubit state can be protected by nesting four layers of UDD sequences. This work indicates that when UDD is applicable (e.g., when environment has a sharp frequency cut-off and when control pulses can be taken as instantaneous pulses), dynamical decoupling using nested UDD sequences is a powerful approach for entanglement protection.

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“…These are the basis of the dynamical decoupling techniques that are applied to beat the decoherence process [26]. Furthermore, even in this very short time scale, the time that each measurement is applied can be very precise, as we can see, for example, in the experimental realization of the Uhrig dynamical decoupling, the Carr-Purcell-Meiboom-Gill-style multipulse spin echo [25], and others. This implies that the scenario studied in the paper is very realistic and that any MBQC realized with ultrafast measurements needs to account for the oscillatory behavior of the dynamics.…”

Section: B Measurements Performed At the Same Timementioning

confidence: 99%

“…Again we see that at times such as t gap = 15.9/ω c , t gap = 31.6/ω c , or t gap = 47.3/ω c , we have a gate fidelity of 96%, 95%, and 93%, respectively, while at times such as t gap = 8.4/ω c , t gap = 24.8/ω c , or t gap = 40.4/ω c , we have a gate fidelity of 22%, 34%, and 44%. It is important to emphasize that ultrafast measurements, which have to be performed in the very short bath correlation time scale, can be produced with current technology [24,25]. These are the basis of the dynamical decoupling techniques that are applied to beat the decoherence process [26].…”

Section: B Measurements Performed At the Same Timementioning

confidence: 99%

Exact dynamics of single-qubit-gate fidelities under the measurement-based quantum computation scheme

et al. 2012

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Measurement-based quantum computation is an efficient model to perform universal computation. Nevertheless, theoretical questions have been raised, mainly with respect to realistic noise conditions. In order to shed some light on this issue, we evaluate the exact dynamics of some single-qubit-gate fidelities using the measurement-based quantum computation scheme when the qubits which are used as a resource interact with a common dephasing environment. We report a necessary condition for the fidelity dynamics of a general pure N -qubit state, interacting with this type of error channel, to present an oscillatory behavior, and we show that for the initial canonical cluster state, the fidelity oscillates as a function of time. This state fidelity oscillatory behavior brings significant variations to the values of the computational results of a generic gate acting on that state depending on the instants we choose to apply our set of projective measurements. As we shall see, considering some specific gates that are frequently found in the literature, the fast application of the set of projective measurements does not necessarily imply high gate fidelity, and likewise the slow application thereof does not necessarily imply low gate fidelity. Our condition for the occurrence of the fidelity oscillatory behavior shows that the oscillation presented by the cluster state is due exclusively to its initial geometry. Other states that can be used as resources for measurement-based quantum computation can present the same initial geometrical condition. Therefore, it is very important for the present scheme to know when the fidelity of a particular resource state will oscillate in time and, if this is the case, what are the best times to perform the measurements.

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Experimental Uhrig dynamical decoupling using trapped ions

Cited by 120 publications

References 37 publications

Protection of quantum systems by nested dynamical decoupling

Protection of quantum systems by nested dynamical decoupling

Protecting unknown two-qubit entangled states by nesting Uhrig’s dynamical decoupling sequences

Exact dynamics of single-qubit-gate fidelities under the measurement-based quantum computation scheme

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