Quantum process tomography and Linblad estimation of a solid-state qubit

Howard, Mark; Twamley, J.; Wittmann, Christoffer; Gaebel, T.; Jelezko, Fedor; Wrachtrup, Jörg

doi:10.1088/1367-2630/8/3/033

Cited by 121 publications

(136 citation statements)

References 34 publications

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“…For example for quantum technology, QPT is used to characterize multi-qubit processors [1] and quantum communication channels [2]; across quantum physics, QPT of some form is often the first experimental investigation of a new physical process-for example, recent research into coherent transport in biological mechanisms [3]. QPT has been demonstrated in a variety of physical systems, including ion traps [4], nuclear magnetic resonance [5], superconducting circuits [6] and nitrogen-vacancy color centers [7]. In the context of photonics, experimental demonstrations have been reported in, e.g., Refs.…”

Section: Introductionmentioning

confidence: 99%

Quantum-enhanced tomography of unitary processes

Zhou¹,

Cable²,

Whittaker³

et al. 2015

Optica

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This is the final published version of the article (version of record). It first appeared online via OSA at https://www.osapublishing.org/optica/abstract.cfm?uri=optica-2-6-510. Please refer to any applicable terms of use of the publisher. University of Bristol -Explore Bristol Research General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. A fundamental task in photonics is to characterize an unknown optical process, defined by properties such as birefringence, spectral response, thickness and flatness. Among many ways to achieve this, single-photon probes can be used in a method called quantum process tomography (QPT). However, the precision of QPT is limited by unavoidable shot noise when implemented using single-photon probes or laser light. In situations where measurement resources are limited, for example, where the process (sample) to be probed is very delicate such that the exposure to light has a detrimental effect on the sample, it becomes essential to overcome this precision limit.Here we devise a scheme for process tomography with a quantum-enhanced precision by drawing upon techniques from quantum metrology. We implement a proof-of-principle experiment to demonstrate this scheme-four-photon quantum states are used to probe an unknown arbitrary unitary process realized with an arbitrary polarization rotation. Our results show a substantial reduction of statistical fluctuations compared to traditional QPT methods-in the ideal case, one four-photon probe state yields the same amount of statistical information as twelve single probe photons.

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Section: Introductionmentioning

confidence: 99%

Quantum-enhanced tomography of unitary processes

Zhou¹,

Cable²,

Whittaker³

et al. 2015

Optica

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“…These include the estimation of quantumoptical gates [8,11,[13][14][15][16][17][18][19], liquid nuclear-magneticresonance gates [20][21][22], superconducting gates [23][24][25][26][27][28] (for a review see Ref. [29]) and other solid-state gates [30][31][32], ion-trap gates [33,34], or the estimation of the dynamics of atoms in optical lattices [35]. In contrast, there are only a very few experimental demonstrations of QPT for infinite-dimensional systems (see, e.g., Ref.…”

Section: Introductionmentioning

confidence: 99%

Efficient tomography of quantum-optical Gaussian processes probed with a few coherent states

Wang

et al. 2013

Phys. Rev. A

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An arbitrary quantum-optical process (channel) can be completely characterized by probing it with coherent states using the recently developed coherent-state quantum process tomography (QPT) [Lobino et al., Science 322, 563 (2008)]. In general, precise QPT is possible if an infinite set of probes is available. Thus, realistic QPT of infinite-dimensional systems is approximate due to a finite experimentally-feasible set of coherent states and its related energy-cut-off approximation. We show with explicit formulas that one can completely identify a quantum-optical Gaussian process just with a few different coherent states without approximations like the energy cut-off. For tomography of multimode processes, our method exponentially reduces the number of different test states, compared with existing methods.

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“…In this regime, the phonon sidebands will be suppressed [20], justifying the three-state approximation of the center where |e α ≡ | 3 E, m = 0 , |g α ≡ | 3 A, 0 and |f s ≡ | 3 A, ±1 for α = s, q. A 2.88 GHz RF field allows a complete control over its ground state transitions [21]. To effect a gate under these conditions implies a 0.1 µs pulse and a technically-challenging static Q of 10 8 for a gate error rate of 10 −3 .…”

Section: Implementing a Controlled Phase Gatementioning

confidence: 79%

High-speed quantum gates with cavity quantum electrodynamics

Greentree

Munro

et al. 2008

Phys. Rev. A

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Cavity quantum electrodynamic schemes for quantum gates are amongst the earliest quantum computing proposals. Despite continued progress and the recent demonstration of photon blockade, there are still issues with optimal coupling and gate operation involving high-quality cavities. Here we show that dynamic cavity control allows for scalable cavity-QED based quantum gates using the full cavity bandwidth. This technique allows an order of magnitude increase in operating speed, and two orders reduction in cavity Q, over passive systems. Our method exploits Stark shift based Q switching, and is ideally suited to solid-state integrated optical approaches to quantum computing.

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Quantum process tomography and Linblad estimation of a solid-state qubit

Cited by 121 publications

References 34 publications

Quantum-enhanced tomography of unitary processes

Quantum-enhanced tomography of unitary processes

Efficient tomography of quantum-optical Gaussian processes probed with a few coherent states

High-speed quantum gates with cavity quantum electrodynamics

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