Exact spin-orbit qubit manipulation

Abstract

We consider exactly solvable manipulation of spin-qubits confined in a moving harmonic trap and in the presence of the time dependent Rashba interaction. Non-adiabatic Anandan phase for cyclic time evolution is compared to the Wilczek-Zee adiabatic counterpart. It is shown that the ratio of these two phases can for a chosen system be any real number. Next we demonstrate the possibility of arbitrary qubit transformation in a ring with spin-orbit interaction. Finally, we present an example of exact analysis of spin-orbit dynamics influenced by the Ornstein-Uhlenbeck coloured noise. a

Quantum systems in and out of equilibrium

“…A third group covers rather different topics, including information entropies, atomic physics or quantum computation. Zozor and coworkers [11] study generalized entropies in quantum and classical statistical theories; Toranzo and coworkers [12] determine the exact values of the Rényi uncertainty measures of D-dimensional harmonic systems; Ramsak et al [13] consider exactly solvable manipulation of spinorbit qubits confined in a moving harmonic trap and in the presence of the time dependent Rashba interaction; lastly, Kastner and Uhrich [14] generalise a former result to prove that special observables exist for which measurement backaction is of no concern when measuring temporal correlations.…”

Controlling spin without magnetic fields: The Bloch-Rashba rotator

“…[22] a method to achieve this was proposed, where an electron trapped in a local potential was moved along a closed trajectory in space, while the Rashba coupling was varied in time, to obtain the desired spin-rotation. An appealing aspect of this system is that exact analytical solutions can be obtained [23][24][25], allowing its robustness towards gate noise [26] and thermal effects [27] to be assessed.…”

Rashba controlled two-electron spin-charge qubits as building blocks of a quantum computer

“…The goal of this paper is to explore how this kind of qubit manipulation device could be further enhanced by exploiting the Rashba spin-orbit coupling 11 , which forces the spin of moving electron to oscillate 12 . Several proposals have been made how this effect could be used to manipulate the state of a qubit, defined as a spincharge state of the electron, by changing its position using electric gates 13 . This can be done by either moving the electron along the line by external potential 14,15 or by moving it around the ring 13,16,17,18 .…”

“…Several proposals have been made how this effect could be used to manipulate the state of a qubit, defined as a spincharge state of the electron, by changing its position using electric gates 13 . This can be done by either moving the electron along the line by external potential 14,15 or by moving it around the ring 13,16,17,18 . It is, therefore, speculated that the addition of the Rashba coupling to the two-electron square quantum dot model of qubit will result in additional possibilities of qubit transformations, controlled by the strength of the Rashba coupling using external voltage gates 19,20 .…”