scholarly journals Three-stage decoherence dynamics of an electron spin qubit in an optically active quantum dot

2015 ◽  
Vol 11 (12) ◽  
pp. 1005-1008 ◽  
Author(s):  
Alexander Bechtold ◽  
Dominik Rauch ◽  
Fuxiang Li ◽  
Tobias Simmet ◽  
Per-Lennart Ardelt ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Electron Spin ◽  
Optically Active ◽  
Spin Qubit

A long-lived spin qubit in an optically active semiconductor quantum dot

2021 ◽  
Author(s):  
Leon Zaporski ◽  
Jonathan H. Bodey ◽  
Noah Shofer ◽  
Santanu Manna ◽  
Daniel M. Jackson ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Optically Active ◽  
Semiconductor Quantum Dot ◽  
Spin Qubit

Engineering Electronic Structure to Protect Phase Memory in Molecular Qubits by Minimising Orbital Angular Momentum

2018 ◽  
Author(s):  
Ana Maria Ariciu ◽  
David H. Woen ◽  
Daniel N. Huh ◽  
Lydia Nodaraki ◽  
Andreas Kostopoulos ◽  
...  
Keyword(s):  
Electron Spin ◽  
Quantum Coherence ◽  
Quantum Information Processing ◽  
Pulse Sequences ◽  
Grover Algorithm ◽  
Ligand Shell ◽  
Information Strategies ◽  
Spin Qubit ◽  
Molecular Spin ◽  
The Impact

Using electron spins within molecules for quantum information processing (QIP) was first proposed by Leuenberger and Loss (1), who showed how the Grover algorithm could be mapped onto a Mn12 cage (2). Since then several groups have examined two-level (S = ½) molecular spin systems as possible qubits (3-12). There has also been a report of the implementation of the Grover algorithm in a four-level molecular qudit (13). A major challenge is to protect the spin qubit from noise that causes loss of phase information; strategies to minimize the impact of noise on qubits can be categorized as corrective, reductive, or protective. Corrective approaches allow noise and correct for its impact on the qubit using advanced microwave pulse sequences (3). Reductive approaches reduce the noise by minimising the number of nearby nuclear spins (7-11), and increasing the rigidity of molecules to minimise the effect of vibrations (which can cause a fluctuating magnetic field via spin-orbit coupling) (9,11); this is essentially engineering the ligand shell surrounding the electron spin. A protective approach would seek to make the qubit less sensitive to noise: an example of the protective approach is the use of clock transitions to render spin states immune to magnetic fields at first order (12). Here we present a further protective method that would complement reductive and corrective approaches to enhancing quantum coherence in molecular qubits. The target is a molecular spin qubit with an effective 2S ground state: we achieve this with a family of divalent rare-earth molecules that have negligible magnetic anisotropy such that the isotropic nature of the electron spin renders the qubit markedly less sensitive to magnetic noise, allowing coherent spin manipulations even at room temperature. If combined with the other strategies, we believe this could lead to molecular qubits with substantial advantages over competing qubit proposals.<br>

scholarly journals Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
George Gillard ◽  
Ian M. Griffiths ◽  
Gautham Ragunathan ◽  
Ata Ulhaq ◽  
Callum McEwan ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Spin Relaxation ◽  
Nuclear Spin ◽  
Operating Conditions ◽  
External Control ◽  
Spin Qubits ◽  
Fundamental Limits ◽  
Trade Offs ◽  
Wide Range ◽  
Spin Qubit

AbstractCombining external control with long spin lifetime and coherence is a key challenge for solid state spin qubits. Tunnel coupling with electron Fermi reservoir provides robust charge state control in semiconductor quantum dots, but results in undesired relaxation of electron and nuclear spins through mechanisms that lack complete understanding. Here, we unravel the contributions of tunnelling-assisted and phonon-assisted spin relaxation mechanisms by systematically adjusting the tunnelling coupling in a wide range, including the limit of an isolated quantum dot. These experiments reveal fundamental limits and trade-offs of quantum dot spin dynamics: while reduced tunnelling can be used to achieve electron spin qubit lifetimes exceeding 1 s, the optical spin initialisation fidelity is reduced below 80%, limited by Auger recombination. Comprehensive understanding of electron-nuclear spin relaxation attained here provides a roadmap for design of the optimal operating conditions in quantum dot spin qubits.

scholarly journals A single-electron probe for buried optically active quantum dot

AIP Advances ◽  
2012 ◽  
Vol 2 (3) ◽  
pp. 032103 ◽  
Author(s):  
T. Nakaoka ◽  
K. Watanabe ◽  
N. Kumagai ◽  
Y. Arakawa
Keyword(s):  
Quantum Dot ◽  
Electron Probe ◽  
Optically Active ◽  
Single Electron

Proposal for optical U(1) rotations of electron spin trapped in a quantum dot

2006 ◽  
Vol 74 (20) ◽  
Author(s):  
Sophia E. Economou ◽  
L. J. Sham ◽  
Yanwen Wu ◽  
D. G. Steel
Keyword(s):  
Quantum Dot ◽  
Electron Spin

scholarly journals Dynamical control of electron spin coherence in a quantum dot: A theoretical study

2007 ◽  
Vol 75 (20) ◽  
Author(s):  
Wenxian Zhang ◽  
V. V. Dobrovitski ◽  
Lea F. Santos ◽  
Lorenza Viola ◽  
B. N. Harmon
Keyword(s):  
Quantum Dot ◽  
Electron Spin ◽  
Theoretical Study ◽  
Spin Coherence ◽  
Dynamical Control

CONTROLLED TELEPORTATION OF ELECTRON SPIN STATE IN QUANTUM DOT VIA SINGLE PHOTON

2008 ◽  
Vol 06 (03) ◽  
pp. 553-560
Author(s):  
YAN-WEI WANG ◽  
MING-FENG WANG ◽  
YI-ZHUANG ZHENG
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Electron Spin ◽  
Spin State ◽  
Faraday Rotation ◽  
Quantum Teleportation ◽  
Single Photon ◽  
Controlled Teleportation ◽  
Controlled Quantum Teleportation ◽  
Qubit System

A controlled quantum teleportation scheme of electron spin state in a quantum dot is proposed. With the entanglement generating through the interaction between the quantum dots in microcavities and a single photon, the controlled teleportation can be implemented using Faraday rotation and single photon measurements. The scheme can be easily generalized to multi-qubit system.

scholarly journals Quantum State Transfer from a Single Photon to a Distant Quantum-Dot Electron Spin

2017 ◽  
Vol 119 (6) ◽  
Author(s):  
Yu He ◽  
Yu-Ming He ◽  
Yu-Jia Wei ◽  
Xiao Jiang ◽  
Kai Chen ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum State ◽  
Electron Spin ◽  
Single Photon ◽  
Quantum State Transfer ◽  
State Transfer

scholarly journals Dynamics of Entanglement between a Quantum Dot Spin Qubit and a Photon Qubit inside a Semiconductor High-Q Nanocavity

2010 ◽  
Vol 2010 ◽  
pp. 1-31 ◽  
Author(s):  
Hubert Pascal Seigneur ◽  
Gabriel Gonzalez ◽  
Michael Niklaus Leuenberger ◽  
Winston Vaughan Schoenfeld
Keyword(s):  
Quantum Dot ◽  
Single Photon ◽  
Hyperfine Interactions ◽  
Interaction Time ◽  
Network Node ◽  
Quantum Network ◽  
Entanglement Dynamics ◽  
High Q ◽  
Spin Qubit

We investigate in this paper the dynamics of entanglement between a QD spin qubit and a single photon qubit inside a quantum network node, as well as its robustness against various decoherence processes. First, the entanglement dynamics is considered without decoherence. In the small detuning regime (Δ=78 μeV), there are three different conditions for maximum entanglement, which occur after 71, 93, and 116 picoseconds of interaction time. In the large detuning regime (Δ=1.5 meV), there is only one peak for maximum entanglement occurring at 625 picoseconds. Second, the entanglement dynamics is considered with decoherence by including the effects of spin-nucleus and hole-nucleus hyperfine interactions. In the small detuning regime, a decent amount of entanglement (35% entanglement) can only be obtained within 200 picoseconds of interaction. Afterward, all entanglement is lost. In the large detuning regime, a smaller amount of entanglement is realized, namely, 25%. And, it lasts only within the first 300 picoseconds.

Sign in / Sign up

Export Citation Format

Share Document