Experimental quantification of entanglement through heat capacity

H Singh,P Gegenwart,Y Tokiwa,C Mitra,H S Jeevan,D Das,T Chakraborty

doi:10.1088/1367-2630/15/11/113001

Abstract

A new experimental realization of heat capacity as an entanglement witness is reported. Entanglement properties of a low–dimensional quantum spin system are investigated by heat capacity measurements performed down to very low temperatures (400 mK), for various applied magnetic field values. The experimentally extracted results for the value of heat capacity at zero field matches perfectly with the theoretical estimates of entanglement from model Hamiltonians. The studied sample is a spin half antiferromagnetic system that shows a clear signature of quantum phase transition at very low temperatures when the heat capacity is varied as a function of fields at a fixed temperature. The variation of entanglement as a function of field is then explored in the vicinity of the quantum phase transition to capture the sudden loss of entanglement.

Highlights

Das et al [14] have quantified entanglement from experimental magnetic susceptibility of copper nitrate (CN) and have shown its variation with field and temperature
I i where alternation parameter α = 0.27 [16]
We report the experimental realization of heat capacity as a new EW

Summary

Introduction

Das et al [14] have quantified entanglement from experimental magnetic susceptibility of CN and have shown its variation with field and temperature. The heat capacity versus temperature measurements, in the range of 400 mK–15 K, was performed at various applied magnetic field values, varying from 0 to 7 T. Wiesniak et al [5] considered the extraction of entanglement from theoretically generated heat capacity curves for certain Hamiltonians, whose variance can be minimized over separable states, as has been done for the transverse field Ising model.

Results

Conclusion