Mesoscopic One-Way Channels for Quantum State Transfer via the Quantum Hall Effect

We show that the one-way channel formalism of quantum optics has a physical realization in electronic systems. In particular, we show that magnetic edge states form unidirectional quantum channels capable of coherently transporting electronic quantum information. Using the equivalence between one-way photonic channels and magnetic edge states, we adapt a proposal for quantum state transfer to mesoscopic systems using edge states as a quantum channel, and show that it is feasible with reasonable experimental parameters. We discuss how this protocol may be used to transfer information encoded in number, charge, or spin states of quantum dots, so it may prove useful for transferring quantum information between parts of a solid-state quantum computer.

Figure 1

Quantum dots coupled to one another and to nearby edge states. Dotted lines indicate tunnel contact. The gray rectangles indicate Ohmic contacts. Dots are labeled as “atom” or “cavity” to make clear the analogy with the atom-optical scheme [6].

Figure 2

(a) QST for charge qubits. (b) QST for spin qubits.