The Generation and Detection of Electron Entanglement

Hanbury Brown and Twiss demonstrated the quantum phenomenon known as “photon bunching” in 1956 using a second-order photon intensity correlation technique, opening the field of photon quantum optics. The study of higher-order correlation functions in photon and atom-cavity systems has subsequently led to a more complete understanding of the quantum statistical and quantum mechanical phenomena resulting from quantum entanglement. With the development of two-dimensional electron gas substrates and nanofabrication techniques, it is now also feasible to consider electron quantum optics, the investigation of higher-order current-correlation functions of electrons and composite particles in mesoscopic devices at cryogenic temperatures. This thesis embodies two general subjects: 1) the generation of electron entanglement, and 2) the detection of electron entanglement. The work can be primarily classified into two experimental and three theoretical efforts. First is the experimental demonstration of “electron anti-bunching” using a Hanbury Brown and Twiss-type intensity interferometer. The electron intensity interferometer and its partner, the electron collision analyzer, constitute an electron quantum optics toolbox that is used to characterize single-electron states and sources. Second is the use of the quantum optics toolbox to experimentally demonstrate and investigate noise suppression at the 0.7 and, more generally, n.m conductance anomalies in quantum point contacts. This noise suppression is strong evidence that a deterministic splitting and, consequently, a natural regulation of the electron flow occurs in quantum point contacts biased to feature conductances away from the integer quantum units. In many cases, deterministic splitting is beyond a single particle picture and, in those cases, may be considered to be a nonlinear effect. Nonlinear deterministic splitting is a necessary,