Transmitting the quantum state of electrons across a metallic island with Coulomb interaction

Abstract

The Coulomb interaction generally limits the quantum propagation of electrons. However, it can also provide a mechanism to transfer their quantum state over larger distances. Here, we demonstrate such a form of teleportation, across a metallic island within which the electrons are trapped much longer than their quantum lifetime. This effect originates from the low temperature freezing of the island's charge Q which, in the presence of a single connected electronic channel, enforces a one-to-one correspondence between incoming and outgoing electrons. Such high-fidelity quantum state imprinting is established between well-separated injection and emission locations, through two-path interferences in the integer quantum Hall regime. The added electron quantum phase of 2πQ e can allow for strong and decoherence-free entanglement of propagating electrons, and notably of flying qubits. arXiv:1902.07569v1 [cond-mat.mes-hall]

Phase-Coherent Dynamics of Quantum Devices with Local Interactions

“…In Section 2 , we give a simple example showing how Coulomb interactions trigger phase-coherent electron state transfer in experiments as those reported in Ref. [ 50 ], Figure 2 . Section 3 discusses how the effective LFL approach [ 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ] provides the unified framework describing such coherent phenomena.…”

“…Such a system was recently realized as a constitutive element of the Mach–Zender interferometer of Ref. [ 50 ], reported in Figure 2 . In that experiment, the observation of fully preserved Mach–Zehnder oscillations, in a system in which a quantum Hall edge state penetrates a metallic floating island demonstrates an interaction-induced, restored phase coherence [ 70 , 71 ].…”

“… Left—Mach–Zehnder interferometer with a floating metallic island (colored in yellow) [ 50 ]. The green lines denote chiral quantum Hall edge states, which can enter the floating island passing through a gate-tunable QPC (in blue).…”

“…As a paradigmatic example, we will focus on recent experiments showing the electron transfer with Coulomb interactions [ 50 ], (see Figure 2 ), and, in more detail, on the mesoscopic capacitor [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ], (see Figure 6). The mesoscopic capacitor does not support the DC transport, and it makes possible the direct investigation and control of the coherent dynamics of charge carriers.…”

Macroscopic Electron Quantum Coherence in a Solid-State Circuit

“…CNOT gates [8,9,11,12]. However, the same Coulomb interaction generally entangles the propagating electrons efficiently with numerous degrees of freedom, including the surrounding electrons, which gives rise to quantum decoherence [1] (see [25] for a notable exception).…”