Quantum entanglement of space domains occupied by interacting electrons

Abstract

Spin-entanglement of two electrons occupying two spatial regions -- domains -- is expressed in a compact form in terms of spin-spin correlation functions. The power of the formalism is demonstrated on several examples ranging from generation of entanglement by scattering of two electrons to the entanglement of a pair of qubits represented by a double quantum dot coupled to leads. In the latter case the collapse of entanglement due to the Kondo effect is analyzed

Thermal entanglement of Hubbard dimers in the nonextensive statistics

“…It is worthwhile to apply the NES to the Hubbard model [54], which is a typical model for strongly correlated fermion systems and which has been widely adopted for a study on quantum information [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Despite the simplicity of the model, however, it is very difficult to obtain its exact solution except for some limited cases.…”

“…Small-scale systems belong to nonextensive systems as mentioned above. It is necessary to take into account the effect of nonextensivity, when we study the properties of quantum information of qubits, which have been mainly investigated within the BGS [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. In recent years, the NES has been applied to the study on quantum information [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53].…”

“…Quantum entanglement is expected to play an essential role as a resource in quantum communication and information processing. Many studies have been made on quantum entanglement with quantum spin models [3][4][5][6][7][8][9][10][11] and fermion systems [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] to clarify both its qualitative and quantitative aspects. The interface between the quantum information and statistical mechanics has been considerably investigated in recent years.…”