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Related papers: Single-shot readout in graphene quantum dots

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In the field of condensed matter, graphene plays a central role as an emerging material for nanoelectronics. Nevertheless, graphene is a semimetal, which constitutes a severe limitation for some future applications. Therefore, a lot of…

Mesoscale and Nanoscale Physics · Physics 2018-10-24 S. Zhao , J. Lavie , L. Rondin , L. Orcin-Chaix , C. Diederichs , Ph. Roussignol , Y. Chassagneux , C. Voisin , K. Müllen , A. Narita , S. Campidelli , J. S. Lauret

We have measured the relaxation time, T1, of the spin of a single electron confined in a semiconductor quantum dot (a proposed quantum bit). In a magnetic field, applied parallel to the two-dimensional electron gas in which the quantum dot…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 R. Hanson , B. Witkamp , L. M. K. Vandersypen , L. H. Willems van Beveren , J. M. Elzerman , L. P. Kouwenhoven

Excited-state quantum phase transitions depend on and reveal the structure of the whole spectrum of many-body systems. While they are theoretically well understood, finding suitable signatures and detect them in actual experiments remains…

Quantum Gases · Physics 2022-01-19 Josep Cabedo , Alessio Celi

Achieving decoherence-free quantum state manipulation is a paramount goal in modern quantum technologies. To this end, we demonstrate its implementation in a two-dimensional dissipative photonic graphene featuring exceptional rings.…

Quantum Physics · Physics 2026-03-11 Qing-Yang Qiu , Guoqing Tian , Zhi-Guang Lu , Franco Nori , Xin-You Lü

We report the preparation and readout of multielectron high-spin states, a three-electron quartet, and a four-electron quintet, in a gate-defined GaAs/AlGaAs single quantum dot using spin filtering by quantum Hall edge states coupled to the…

Mesoscale and Nanoscale Physics · Physics 2021-09-01 H. Kiyama , K. Yoshimi , T. Kato , T. Nakajima , A. Oiwa , S. Tarucha

We report initialization, complete electrical control, and single-shot readout of an exchange-only spin qubit. Full control via the exchange interaction is fast, yielding a demonstrated 75 qubit rotations in under 2 ns. Measurement and…

Mesoscale and Nanoscale Physics · Physics 2013-09-09 J. Medford , J. Beil , J. M. Taylor , S. D. Bartlett , A. C. Doherty , E. I. Rashba , D. P. DiVincenzo , H. Lu , A. C. Gossard , C. M. Marcus

We report a single-shot-based projective readout of a semiconductor hybrid qubit formed by three electrons in a GaAs double quantum dot. Voltage-controlled adiabatic transitions between the qubit operations and readout conditions allow…

We demonstrate a new method for projective single-shot measurement of two electron spin states (singlet versus triplet) in an array of gate-defined lateral quantum dots in GaAs. The measurement has very high fidelity and is robust with…

We report the fabrication of electrostatically defined nanostructures in encapsulated bilayer graphene, with leakage resistances below depletion gates as high as $R \sim 10~$G$\Omega$. This exceeds previously reported values of $R =~$10 -…

Quantum annealing has been demonstrated with superconducting qubits. Such a quantum annealer has been used to solve combinatorial optimization problems. Moreover, it serves as a quantum simulator for investigating the properties of quantum…

Quantum Physics · Physics 2025-07-16 Takashi Imoto , Yuki Susa , Ryoji Miyazaki , Yuichiro Matsuzaki

We consider graph states generated by the action of controlled phase shift operators on a separable state of a multi-qubit system. The case when all the qubits are initially prepared in arbitrary states is investigated. We obtain the…

Quantum Physics · Physics 2024-01-29 N. A. Susulovska

We consider electron spin qubits in quantum dots and define a measurement efficiency e to characterize reliable measurements via n-shot read outs. We propose various implementations based on a double dot and quantum point contact (QPC) and…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Hans-Andreas Engel , Vitaly Golovach , Daniel Loss , L. M. K. Vandersypen , J. M. Elzerman , R. Hanson , L. P. Kouwenhoven

Excited states of spin-chains play an important role in condensed matter physics. We present a method of calculating the single magnon excited states of the Heisenberg spin-chain that can be efficiently implemented on a quantum processor…

Strongly Correlated Electrons · Physics 2022-11-23 Shashank Kumar Ranu , Daniel D. Stancil

We study a graphene double quantum dot in different coupling regimes. Despite the strong capacitive coupling between the dots, the tunnel coupling is below the experimental resolution. We observe additional structures inside the finite-bias…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 F. Molitor , H. Knowles , S. Dröscher , U. Gasser , T. Choi , P. Roulleau , J. Güttinger , A. Jacobsen , C. Stampfer , K. Ensslin , T. Ihn

We review progress on the spintronics proposal for quantum computing where the quantum bits (qubits) are implemented with electron spins. We calculate the exchange interaction of coupled quantum dots and present experiments, where the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Hans-Andreas Engel , L. P. Kouwenhoven , Daniel Loss , C. M. Marcus

We report on microscopic measurements of the low-energy electronic structures both at zigzag and armchair edges of bilayer graphene using scanning tunneling microscopy and spectroscopy (STM and STS). We have found that, both in the absence…

Mesoscale and Nanoscale Physics · Physics 2016-03-23 Long-Jing Yin , Yu Zhang , Jia-Bin Qiao , Si-Yu Li , Lin He

A primary method of reading out a quantum dot hybrid qubit involves projection of the logical basis onto distinct charge states that are readily detected by an integrated charge sensing dot. However, in the simplest configuration, the…

We study the dynamics of a single electron spin in a double quantum dot (DQD) and its readout via a quantum point contact (QPC). We model the system microscopically and derive rate equations for the reduced electron density matrix of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Jian-Ping Zhang , Shi-Hua Ouyang , Chi-Hang Lam , J. Q. You

The magnetic field dependence of energy levels in gapped single- and bilayer graphene quantum dots (QDs) defined by electrostatic gates is studied analytically in terms of the Dirac equation. Due to the absence of sharp edges in these types…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Patrik Recher , Johan Nilsson , Guido Burkard , Bjoern Trauzettel

We study the excitation spectroscopy of few-electron, parallel coupled double quantum dots (QDs). By applying a finite source drain voltage to a double QD (DQD), the first excited states observed in nonequilibrium charging diagrams can be…

Mesoscale and Nanoscale Physics · Physics 2013-07-01 T. Hatano , Y. Tokura , S. Amaha , T. Kubo , S. Teraoka , S. Tarucha