Entanglement Production in a Chaotic Quantum Dot

Abstract

It has lecently been shown theoietically that elastic scattenng in the Fermi sea pioduces quantum mechanically entangled states The mechamsm is similai to entanglement by a beam sphttei in optics, but a key distmction is that the electromc mechamsm woiks even if the somce is m local theimal equilibimm An expeiimental leahzation was pioposed usmg tunnelmg between two edge channels in a stiong magnetic field Heie we investigate a low magnetic iield alternative, usmg multiple scattenng in a quantum dot Two pairs of smgle-channel pomt contacts define a pau of qubits If the scattenng is chaotic, a umveisal statistical descnption of the entanglement production (quantified by the concurrence) is possible The mean concunence tuins out to be almost mdependent on whethei time leveisal symmetry is bioken 01 not We show how the concunence can be extracted fiom a Bell inequahty usmg low-frequency noise measurements, without requmng the tunnelmg assumption of earhei woik

Orbital entanglement and electron localization in quantum wires

“…This resembles the orbital entanglers proposed in Refs. [18][19][20], provided the chaotic quantum dot is replaced by a disordered quantum wire. A low bias voltage between reservoirs leads to a coherent current along the wire from left to right.…”

“…,4. The |2,0 and |0,2 , instead, are separable in terms of the bipartition left-right [16,[18][19][20]. An electron leaving the quantum wire to the left side can choose between lead 1 and lead 2 for escaping (see Fig.…”

“…Those states with 0 < C < 1 are partly entangled states. It turns out that the concurrence is determined by the scattering amplitudes and can be written in terms of the transmission eigenvalues τ 1 and τ 2 of the product tt † as [16,18] …”

“…Effects of quantum chaotic scattering on orbital entanglement production in quantum dots have been studied in the past [16,[18][19][20][21][22][23]. In these ballistic microstructures, electrons are elastically scattered, while the chaotic character of the scattering produces stochastic fluctuations of the orbital entanglement.…”

Voltage probe model of spin decay in a chaotic quantum dot with applications to spin-flip noise and entanglement production

“…The two effects are fundamentally connected, in the sense that the degree to which spin-up and spin-down current fluctuations are correlated provides a measure of the degree of spin entanglement of electron-hole pairs exiting the quantum dot. 2 The geometry is sketched in Fig. 1.…”