Engineering of an all-heteronuclear 5-qubit NMR quantum computer

Marx, Raimund; Pomplun, Nikolas; Bermel, Wolfgang; Zeiger, Heinz; Engelke, Frank; Fahmy, Amr; Glaser, Steffen J.

doi:10.1002/mrc.4233

Cited by 9 publications

(13 citation statements)

References 54 publications

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“…We observe experimentally that quantum coherence in a composite system, whose subsystems are all affected by decoherence, can remain de facto invariant for arbitrarily long time without any external control. This phenomenon was recently predicted to occur for a particular family of initial states of quantum systems of any (however large) even num-ber of qubits [25], and is here demonstrated in a room temperature liquid-state nuclear magnetic resonance (NMR) quantum simulator [29][30][31][32][33] with two different molecules, encompassing two-qubit and four-qubit spin ensembles. After initialisation into a so-called generalised Bell diagonal state [25], the multiqubit ensemble is left to evolve under naturally occurring phase damping noise.…”

mentioning

confidence: 76%

“…The four-qubit experiment was performed in a BRUKER AVIII 600 MHz spectrometer equipped with a prototype 6-channel probe head as described in the main text, see [32] for further details.…”

Section: A Nmr Setupmentioning

confidence: 99%

“…The molecule chosen to encode the 4-qubit spin system was the 13 C O -15 Ndiethyl-(dimethylcarbamoyl)fluoromethyl-phosphonate compound, whose coupling topology is shown in Fig. 3A; a detailed description of its synthesis can be found again in [32]. This molecule contains 5 NMR-active spins ( 1 H, 19 F, 13 C, 31 P and 15 N).…”

Section: A Nmr Setupmentioning

confidence: 99%

“…Finally, we investigated experimentally the resilience of coherence in a larger system, composed of four logical qubits. To this aim, we performed a more advanced NMR demonstration in a BRUKER AVIII 600 MHz spectrometer equipped with a prototype 6-channel probe head, allowing full and independent control of up to 5 different nuclear spins [30,32]. We used the 13 C O -15 N-diethyl-(dimethylcarbamoyl)fluoromethylphosphonate compound [32], whose coupling topology is shown in Fig.…”

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confidence: 99%

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Observation of Time-Invariant Coherence in a Nuclear Magnetic Resonance Quantum Simulator

et al. 2016

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The ability to live in coherent superpositions is a signature trait of quantum systems and constitutes an irreplaceable resource for quantum-enhanced technologies. However, decoherence effects usually destroy quantum superpositions. It was recently predicted that, in a composite quantum system exposed to dephasing noise, quantum coherence in a transversal reference basis can stay protected for an indefinite time. This can occur for a class of quantum states independently of the measure used to quantify coherence, and it requires no control on the system during the dynamics. Here, such an invariant coherence phenomenon is observed experimentally in two different setups based on nuclear magnetic resonance at room temperature, realizing an effective quantum simulator of two- and four-qubit spin systems. Our study further reveals a novel interplay between coherence and various forms of correlations, and it highlights the natural resilience of quantum effects in complex systems.

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mentioning

confidence: 76%

“…The four-qubit experiment was performed in a BRUKER AVIII 600 MHz spectrometer equipped with a prototype 6-channel probe head as described in the main text, see [32] for further details.…”

Section: A Nmr Setupmentioning

confidence: 99%

Section: A Nmr Setupmentioning

confidence: 99%

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confidence: 99%

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Observation of Time-Invariant Coherence in a Nuclear Magnetic Resonance Quantum Simulator

et al. 2016

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“…We introduce a system of 5 coupled spins [29,30], the evolution of which is described by the following Hamiltonian:…”

Section: A Control Of a System Of Five Coupled Spinsmentioning

confidence: 99%

Fully efficient time-parallelized quantum optimal control algorithm

et al. 2016

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We present a time-parallelization method that enables to accelerate the computation of quantum optimal control algorithms. We show that this approach is approximately fully efficient when based on a gradient method as optimization solver: the computational time is approximately divided by the number of available processors. The control of spin systems, molecular orientation and BoseEinstein condensates are used as illustrative examples to highlight the wide range of application of this numerical scheme.

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