Scaling behavior of electron decoherence in a graphene Mach-Zehnder interferometer

Jo, Moon Ho; Lee, June-Young M.; Assouline, Alexandre; Brasseur, Paul; Watanabe, Kenji; Taniguchi, Takashi; Roche, P.; Glattli, Christian; Kumada, N.; Parmentier, François; Sim, Hyun Sub; Roulleau, Preden

doi:10.1038/s41467-022-33078-2

Cited by 7 publications

(9 citation statements)

References 29 publications

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“…The functioning of the MZI depends crucially on the phase coherence of the electronic wave functions traveling along the two paths. Thus, it is natural that the MZI can also be used to detect decoherence and measure, e.g., the electron's coherence length and how it is influenced by parameters such as temperature [64,41,39]. Furthermore, the MZI can be used to learn about properties of the carriers producing the signal, e.g., to measure the degree of indistinguishability of electrons [8,9], or the statistics of the charge carriers in the device [38].…”

Section: Other Applicationsmentioning

confidence: 99%

“…With these fundamental components one can consider building a GNR-based Mach-Zehnder-like interferometer, which can be used for a variety of tasks from sensing of magnetic fluxes or local electric fields to measuring indistinguishability [9], statistics [38], and coherence length [39] of the charge carriers or generating entanglement between them [40,41,42]. Other two-path setups have been demonstrated to act as a manipulable flying qubit architecture [43] using the Aharonov-Bohm (AB) effect [44].…”

Section: Introductionmentioning

confidence: 99%

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Mach--Zehnder-like interferometry with graphene nanoribbon networks

Sanz¹,

Papior²,

Giedke³

et al. 2023

Preprint

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We study theoretically electron interference in a Mach-Zehnder-like geometry formed by four zigzag graphene nanoribbons (ZGNRs) arranged in parallel pairs, one on top of the other, such that they form intersection angles of 60 • . Depending on the interribbon separation, each intersection can be tuned to act either as an electron beam splitter or as a mirror, enabling tuneable circuitry with interfering pathways. Based on the mean-field Hubbard model and Green's function techniques, we evaluate the electron transport properties of such 8-terminal devices and identify pairs of terminals that are subject to self-interference. We further show that the scattering matrix formalism in the approximation of independent scattering at the four individual junctions provides accurate results as compared with the Green's function description, allowing for a simple interpretation of the interference process between two dominant pathways. This enables us to characterize the device sensitivity to phase shifts from an external magnetic flux according to the Aharonov-Bohm effect as well as from small geometric variations in the two path lengths. The proposed devices could find applications as magnetic field sensors and as detectors of phase shifts induced by local scatterers on the different segments, such as adsorbates, impurities or defects. The setup could also be used to create and study quantum entanglement.

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Section: Other Applicationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mach--Zehnder-like interferometry with graphene nanoribbon networks

Sanz¹,

Papior²,

Giedke³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Thus, it is natural that the MZI can also be used to detect decoherence and measure, e.g. the electron's coherence length and how it is influenced by parameters such as temperature [39,41,65]. Furthermore, the MZI can be used to learn about properties of the carriers producing the signal, e.g.…”

Section: Other Applicationsmentioning

confidence: 99%

“…With these fundamental components one can consider building a GNR-based Mach-Zehnder-like interferometer (MZI), which can be used for a variety of tasks from sensing of magnetic fluxes or local electric fields to measuring indistinguishability [9], statistics [38], and coherence length [39] of the charge carriers or generating entanglement between them [40][41][42]. Other two-path setups have been demonstrated to act as a manipulable flying qubit architecture [43] using the AB effect [44].…”

Section: Introductionmentioning

confidence: 99%

Mach–Zehnder-like interferometry with graphene nanoribbon networks

Wuhl

Papior

Giedke

et al. 2023

J. Phys.: Condens. Matter

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We study theoretically electron interference in a Mach-Zehnder-like geometry formed by four zigzag graphene nanoribbons (ZGNRs) arranged in parallel pairs, one on top of the other, such that they form intersection angles of 60º. Depending on the interribbon separation, each intersection can be tuned to act either as an electron beam splitter or as a mirror, enabling tuneable circuitry with interfering pathways. Based on the mean-field Hubbard model and Green's function techniques, we evaluate the electron transport properties of such 8-terminal devices and identify pairs of terminals that are subject to self-interference. We further show that the scattering matrix formalism in the approximation of independent scattering at the four individual junctions provides accurate results as compared with the Green's function description, allowing for a simple interpretation of the interference process between two dominant pathways. This enables us to characterize the device sensitivity to phase shifts from an external magnetic flux according to the Aharonov-Bohm effect as well as from small geometric variations in the two path lengths. The proposed devices could find applications as magnetic field sensors and as detectors of phase shifts induced by local scatterers on the different segments, such as adsorbates, impurities or defects. The setup could also be used to create and study quantum entanglement.

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“…Nevertheless, a basic quantum manipulation of an on-demand and propagating single electron is still missing ( 9 ), primarily owing to the short coherence length ( 3 ) of excited electrons in conventional semiconductors. This problem could be solved by using graphene, a two-dimensional atomically thin material, which shows outstanding coherence properties under relatively large bias ( 10 , 11 ). Owing to its valley pseudospin degrees of freedom, graphene provides a very promising platform.…”

mentioning

confidence: 99%

Emission and coherent control of Levitons in graphene

Assouline,

Pugliese,

Chakraborti

et al. 2023

Science

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Flying qubits encode quantum information in propagating modes instead of stationary discrete states. Although photonic flying qubits are available, the weak interaction between photons limits the efficiency of conditional quantum gates. Conversely, electronic flying qubits can use Coulomb interactions, but the weaker quantum coherence in conventional semiconductors has hindered their realization. In this work, we engineered on-demand injection of a single electronic flying qubit state and its manipulation over the Bloch sphere. The flying qubit is a Leviton propagating in quantum Hall edge channels of a high-mobility graphene monolayer. Although single-shot qubit readout and two-qubit operations are still needed for a viable manipulation of flying qubits, the coherent manipulation of an itinerant electronic state at the single-electron level presents a highly promising alternative to conventional qubits.

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Scaling behavior of electron decoherence in a graphene Mach-Zehnder interferometer

Cited by 7 publications

References 29 publications

Mach--Zehnder-like interferometry with graphene nanoribbon networks

Mach--Zehnder-like interferometry with graphene nanoribbon networks

Mach–Zehnder-like interferometry with graphene nanoribbon networks

Emission and coherent control of Levitons in graphene

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