Experimental determination of thermal entanglement in spin clusters using magnetic susceptibility measurements

Abstract

The present work reports an experimental observation of thermal entanglement in a clusterized spin chain formed in the compound Na2Cu5Si4O14. The presence of entanglement was investigated through two measured quantities, an Entanglement Witness and the Entanglement of Formation, both derived from the magnetic susceptibility. It was found that pairwise entanglement exists below ∼ 200 K. Tripartite entanglement was also observed below ∼ 240 K. A theoretical study of entanglement evolution as a function of applied field and temperature is also presented.

Carboxylate-based molecular magnet: One path toward achieving stable quantum correlations at room temperature

“…In spite of that, it is fragile and can easily vanish due to the inevitable interaction of the system with its environment [4]; and due to this condition, it was thought that entanglement could only exist at low temperatures. However, recently, it has been shown that entanglement can also exist at higher temperatures, and can be detected through the measurement of some thermodynamic observables [5][6][7][8][9][10][11][12][13][14][15][16][17].…”

“…In spite of that, it is fragile and can easily vanish due to the inevitable interaction of the system with its environment [4]; and due to this condition, it was thought that entanglement could only exist at low temperatures. However, recently, it has been shown that entanglement can also exist at higher temperatures, and can be detected through the measurement of some thermodynamic observables [5][6][7][8][9][10][11][12][13][14][15][16][17].Nevertheless, quantum entanglement does not encompass all quantum correlations in a system and recent studies have greatly expanded the notion of quantum correlations [18][19][20][21][22][23][24][25][26][27][28][29]; and the measure of quantum excess of correlations has been named as quantum discord [19][20][21]. In the last years, it was understood that quantum discord has an important role in many quantum information processing even without entanglement.…”

Entanglement, magnetic and quadrupole moments properties of the mixed spin Ising–Heisenberg diamond chain

“…Thermal entanglement was detected by both experimental [13,14,15] and theoretical [16] observations at low dimensional spin systems, formed in compounds.…”

Thermal entanglement between non-nearest-neighbor spins on fractal lattices

“…For spin systems can be used for gate operation in quantum computer thermal entanglement on solid spin systems have been widely studied, for example, the Heisenberg spin chain both in the absence [8] and presence [9,10] of an external magnetic field , spin rings [11] and spin clusters [12,13]. However, most of these works only focused on thermal entanglement between nearest, next-nearest or next-to-next-nearest neighbor spins [14][15][16][17][18][19].…”

“…However, most of these works only focused on thermal entanglement between nearest, next-nearest or next-to-next-nearest neighbor spins [14][15][16][17][18][19]. This motivate us to propose two questions: (i) Can thermal entanglement exist between distant non-nearestneighbor sites in spin system?…”