scholarly journals Exact analytical treatment of multiqubit noisy dynamics in exchange-coupled semiconductor spin qubits

2021 ◽  
Vol 103 (20) ◽  
Author(s):  
Donovan Buterakos ◽  
Sankar Das Sarma
Keyword(s):  
Spin Qubits ◽  
Analytical Treatment ◽  
Coupled Semiconductor

scholarly journals Dynamics of two coupled semiconductor spin qubits in a noisy environment

2016 ◽  
Vol 94 (4) ◽  
Author(s):  
S. Das Sarma ◽  
Robert E. Throckmorton ◽  
Yang-Le Wu
Keyword(s):  
Noisy Environment ◽  
Spin Qubits ◽  
Coupled Semiconductor

Atomic Imaging of Crystals using Large-Angle Electron Scattering in STEM

1990 ◽  
Vol 48 (1) ◽  
pp. 74-75
Author(s):  
D.E. Jesson ◽  
S. J. Pennycook
Keyword(s):  
Wave Function ◽  
Electron Scattering ◽  
Numerical Solutions ◽  
Large Angle ◽  
Real Space ◽  
High Angle ◽  
Analytical Treatment ◽  
Order Zero ◽  
Experimental Conditions ◽  
Ewald Sphere

It is well known that conventional atomic resolution electron microscopy is a coherent imaging process best interpreted in reciprocal space using contrast transfer function theory. This is because the equivalent real space interpretation involving a convolution between the exit face wave function and the instrumental response is difficult to visualize. Furthermore, the crystal wave function is not simply related to the projected crystal potential, except under a very restrictive set of experimental conditions, making image simulation an essential part of image interpretation. In this paper we present a different conceptual approach to the atomic imaging of crystals based on incoherent imaging theory. Using a real-space analysis of electron scattering to a high-angle annular detector, it is shown how the STEM imaging process can be partitioned into components parallel and perpendicular to the relevant low index zone-axis.It has become customary to describe STEM imaging using the analytical treatment developed by Cowley. However, the convenient assumption of a phase object (which neglects the curvature of the Ewald sphere) fails rapidly for large scattering angles, even in very thin crystals. Thus, to avoid unpredictive numerical solutions, it would seem more appropriate to apply pseudo-kinematic theory to the treatment of the weak high angle signal. Diffraction to medium order zero-layer reflections is most important compared with thermal diffuse scattering in very thin crystals (<5nm). The electron wave function ψ(R,z) at a depth z and transverse coordinate R due to a phase aberrated surface probe function P(R-RO) located at RO is then well described by the channeling approximation;

Storage ring FEL dynamics: an analytical treatment

1988 ◽  
Vol 101 (6) ◽  
pp. 703-714 ◽  
Author(s):  
G. Dattoli ◽  
L. Giannessi ◽  
H. Fang ◽  
A. Renieri ◽  
A. Torre
Keyword(s):  
Storage Ring ◽  
Analytical Treatment

Independently synchronizable groups in networks of delay-coupled semiconductor lasers

2021 ◽  
pp. 1-1
Author(s):  
Liyue Zhang ◽  
Wei Pan ◽  
Lianshan Yan ◽  
Bin Luo ◽  
Xihua Zou ◽  
...  
Keyword(s):  
Semiconductor Lasers ◽  
Coupled Semiconductor

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.

Sign in / Sign up

Export Citation Format

Share Document