Tunneling Statistics for Analysis of Spin-Readout Fidelity

Gorman, Samuel K.; He, Yu; House, Matthew; Keizer, J. G.; Keith, D. A.; Fricke, Lukas; Hile, Samuel J.; Broome, Matthew A.; Simmons, M. Y.

doi:10.1103/physrevapplied.8.034019

Cited by 18 publications

(25 citation statements)

References 38 publications

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“…3b) to partition the distributions such that values above were considered to be singlet states and values below were considered to be triplet states. We determined that the optimal threshold to maximise the readout fidelity was 0.157 [26,27]. This yielded an average single-spin readout fidelity, of the single-gate RF sensor, of 82.9% (where the singlet and triplet readout fidelities were 78.2% and 87.6% respectively).…”

Section: Resultsmentioning

confidence: 99%

Single-Shot Single-Gate rf Spin Readout in Silicon

et al. 2018

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For solid-state spin qubits, single-gate RF readout can help minimise the number of gates required for scale-up to many qubits since the readout sensor can integrate into the existing gates required to manipulate the qubits [1,2]. However, a key requirement for a scalable quantum computer is that we must be capable of resolving the qubit state within single-shot, that is, a single measurement [3].Here we demonstrate single-gate, single-shot readout of a singlet-triplet spin state in silicon, with an average readout fidelity of 82.9% at a 3.3 kHz measurement bandwidth. We use this technique to measure a triplet T− to singlet S0 relaxation time of 0.62 ms in precision donor quantum dots in silicon. We also show that the use of RF readout does not impact the maximum readout time at zero detuning limited by the S0 to T− decay, which remained at approximately 2 ms. This establishes single-gate sensing as a viable readout method for spin qubits.

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Section: Resultsmentioning

confidence: 99%

Single-Shot Single-Gate rf Spin Readout in Silicon

et al. 2018

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“…[28][29][30] Recently, waiting time distributions have been measured both for photon emission 3 and electron tunneling. 54 The waiting time distribution can be obtained as W(τ ) = τ ∂ 2 τ Π(τ ), where τ is the mean waiting time and Π(τ ) is the probability that no photons are emitted in a time span of duration τ . 31,32 Physically, the time-derivatives correspond to a photon emission at the beginning and the end of the time interval.…”

Section: Waiting Time Distributionmentioning

confidence: 99%

Photon counting statistics of a microwave cavity

2019

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The development of microwave photon detectors is paving the way for a wide range of quantum technologies and fundamental discoveries involving single photons. Here, we investigate the photon emission from a microwave cavity and find that distribution of photon waiting times contains information about few-photon processes, which cannot easily be extracted from standard correlation measurements. The factorial cumulants of the photon counting statistics are positive at all times, which may be intimately linked with the bosonic quantum nature of the photons. We obtain a simple expression for the rare fluctuations of the photon current, which is helpful in understanding earlier results on heat transport statistics and measurements of work distributions. Under non-equilibrium conditions, where a small temperature gradient drives a heat current through the cavity, we formulate a fluctuation-dissipation relation for the heat noise spectra. Our work suggests a number of experiments for the near future, and it offers theoretical questions for further investigation. arXiv:1808.02716v3 [cond-mat.mes-hall]

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“…Experimentally, the tunneling of electrons can be measured in real-time with charge detectors. 51,52 In order to calculate the relevant waiting times, we assume negatively biased ferromagnetic leads in the way that relevant quantum dots' levels are deep in the transport window. Then, tunneling has a unidirectional character and the system can be described with the aid of Markovian quantum master equation for the reduced density matrixρ 61-64…”

Section: Waiting Time Distributionmentioning

confidence: 99%

“…49 It is also important to note that waiting time distributions for electrons are already accessible in experiments on quantum dot systems. [50][51][52] All the aforementioned transport characteristics are studied in two specific gate voltage detuning schemes: in a symmetric and in an antisymmetric one.…”

Section: Introductionmentioning

confidence: 99%

Current cross-correlations and waiting time distributions in Andreev transport through Cooper pair splitters based on a triple quantum dot system

Wrześniewski¹,

Weymann²

2020

Phys. Rev. B

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We study the spin-resolved subgap transport in a triple quantum-dot system coupled to one superconducting and two ferromagnetic leads. We examine the Andreev processes in the parallel and antiparallel alignments of ferromagnets magnetic moments in both the linear and nonlinear response regimes. The emphasis is put on the analysis of the current cross-correlations between the currents flowing through the left and right arms of the device and relevant electron waiting time distributions. We show that both quantities can give an important insight into the subgap transport processes and their analysis can help optimizing the system parameters for achieving the considerable Andreev current and efficient Cooper pair splitting. Strong positive values of cross-correlations are associated with the presence of tunneling processes enhancing the Cooper pair splitting efficiency, while short waiting times for electrons tunneling through distinct ferromagnetic contacts indicate fast splitting of emitted Cooper pairs. In particular, we study two detuning schemes and show that antisymmetric shift of side quantum dots energy levels is favorable for efficient Cooper pair splitting. The analysis of spin-resolved waiting time distributions supports the performance enhancement due to the presence of ferromagnetic contacts, which is in particular revealed for short times. Finally, we consider the effect of changing the inter-dot hopping amplitude and predict that strong inter-dot correlations lead to a reduction of Andreev transport properties in low-bias limit.arXiv:2003.09165v1 [cond-mat.mes-hall]

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Tunneling Statistics for Analysis of Spin-Readout Fidelity

Cited by 18 publications

References 38 publications

Single-Shot Single-Gate rf Spin Readout in Silicon

Single-Shot Single-Gate rf Spin Readout in Silicon

Photon counting statistics of a microwave cavity

Current cross-correlations and waiting time distributions in Andreev transport through Cooper pair splitters based on a triple quantum dot system

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