## The More You Know: Loss-DiVicenzo Quantum Computer

The Loss-DiVicenzo Quantum Computer is a hardware proposal for the implementation of a scalable spin-based quantum computer in a coupled quantum dot system. The qubits of their quantum computer are realized as the two spin states of a confined electron.

In this proposal, initialization is achieved by applying a strong magnetic field and letting the electrons reach their thermodynamic ground state. Single-qubit operations are performed by varying the effective Zeeman interaction on each dot individually.

Two-qubit quantum gate operations are performed by controlling the electrostatic barrier between neighbouring quantum dots. Thus, if the barrier potential is high, the electrons cannot tunnel from one quantum dot to another and the spins are decoupled. When the barrier is pulsed to a low voltage, the two electron wave functions overlap and the spins will be subject to a non-zero Heisenberg exchange coupling:

$H_{s}(t)=J(t)\vec{S}_1\cdot\vec{S}_2$.

Finally, readout could be performed using spin-to-charge conversion (high-fidelity, single-shot electron charge detection).

References:

[1] “Quantum Computation with Quantum Dots”, D. Lossa, and D. P. DiVincenzo. arXiv:cond-mat/9701055