All electrically controlled quantum gates for single heavy hole spin qubits

TL;DR

This paper proposes and simulates nanodevices capable of performing all basic single-qubit quantum gates on heavy hole spin qubits using purely electrical control, enabling ultrafast and scalable quantum computing.

Contribution

It introduces a set of electrically controlled nanodevices for all fundamental single heavy hole spin qubit gates, supported by detailed Poisson-Schrödinger simulations.

Findings

Devices can perform all basic single-qubit gates electrically.

Gate operations are ultrafast, on the order of tens of picoseconds.

The approach supports scalable quantum computing architectures.

Abstract

In this paper, several nanodevices which realize basic single heavy hole qubit operations are proposed and supported by time dependent self consistent Poisson-Schr\"{o}dinger calculations using a four band heavy hole-light hole model. In particular we propose a set of nanodevices which can act as Pauli X, Y, Z quantum gates and as a gate that acts similar as a Hadamard gate (i.e. it creates a balanced superposition of basis states but with an additional phase factor) on the heavy hole spin qubit. We also present the design and simulation of a gated semiconductor nanodevice which can realize an arbitrary sequence of all these proposed single quantum logic gates. The proposed devices exploit the self-focusing effect of the hole wave function which allows for guiding the hole along a given path in the form of a stable soliton-like wave packet. Thanks to the presence of the Dresselhaus spin orbit coupling, the motion of the hole along a certain direction is equivalent to the application of an effective magnetic field which induces in turn a coherent rotation of the heavy hole spin. The hole motion and consequently the quantum logic operation is initialized only by weak static voltages applied to the electrodes which cover the nanodevice. The proposed gates allow for an all electric and ultrafast (tens of picoseconds) heavy hole spin manipulation and give the possibility to implement a scalable architecture of heavy hole spin qubits for quantum computation applications.