Quantum circuits based on coded qubits encoded in chirality of electron spin complexes in triple quantum dots

Abstract

We present a theory of quantum circuits based on coded qubits encoded in chirality of electron spin complexes in lateral gated semiconductor triple quantum dot molecules with one-electron spin in each dot. Using microscopic Hamiltonian we show how to initialize, coherently control, and measure the quantum state of a chirality-based coded qubit using static magnetic field and voltage tuning of individual dots. The microscopic model of two interacting coded qubits is established and mapped to an Ising Hamiltonian, resulting in nonlocal double-qubit gates.

Herzberg circuit and Berry's phase in chirality-based coded qubit in a triangular triple quantum dot

“…The two-level system, a qubit, is encoded in the two degenerate states of a three-spin complex with total spin S = 1/2. [13][14][15] An early proposal to generate the geometrical phase in degenerate one-electron quantum levels of a three-atom system was discussed by Herzberg and Longuet-Higgins in Ref. 1 in 1963.…”

Readout and dynamics of a qubit built on three quantum dots

“…Recently Georgeot and Mila [25] suggested to build the qubit on two opposite chiral states generated by a magnetic flux penetrating the triangular TQD. One can use also a special configuration of magnetic fields (one in-plane and perpendicular to the TQD system) to encode a qubit in chirality states [26]. Recent progres in theory and experiment with TQD system was reported in [27].…”

Entanglement in a three spin system controlled by electric and magnetic fields

“…Recently Hsieh et al [38] proposed to use chirality for quantum computations. Their quantum circuits are based on qubits encoded in chirality of electron spin complexes in systems of triangular quantum dot molecules.…”

“…In the presence of the magnetic flux (φ = 0) chirality of the spin system [described by the last term in (16)] becomes relevant [32][33][34][35][36][37][38]. Recently Hsieh et al [38] proposed to use chirality for quantum computations.…”