Elements of information theory
Elements of information theory
Quantum computation and quantum information
Quantum computation and quantum information
Entanglement of dipolar coupling spins
Quantum Information Processing
Entanglement in dipolar coupling spin system in equilibrium state
Quantum Information Processing
| Hi-index | 0.00 |
The behavior of total quantum correlations (discord) in dimers consisting of dipolar-coupled spins 1/2 are studied. We found that the discord $$Q=0$$ Q = 0 at absolute zero temperature. As the temperature $$T$$ T increases, the quantum correlations in the system increase at first from zero to its maximum and then decrease to zero according to the asymptotic law $$T^{-2}$$ T - 2 . It is also shown that in absence of external magnetic field $$B$$ B , the classical correlations $$C$$ C at $$T\rightarrow 0$$ T 驴 0 are, vice versa, maximal. Our calculations predict that in crystalline gypsum $$\hbox {CaSO}_{4}\cdot \hbox {2H}_{2}{\hbox {O}}$$ CaSO 4 · 2H 2 O the value of natural $$(B=0)$$ ( B = 0 ) quantum discord between nuclear spins of hydrogen atoms is maximal at the temperature of 0.644 $$\upmu $$ μ K, and for 1,2-dichloroethane $$\hbox {H}_{2}$$ H 2 ClC--- $$\hbox {CH}_{2}{\hbox {Cl}}$$ CH 2 Cl the discord achieves the largest value at $$T=0.517~\upmu $$ T = 0.517 μ K. In both cases, the discord equals $$Q\approx 0.083$$ Q 驴 0.083 bit/dimer what is $$8.3\,\%$$ 8.3 % of its upper limit in two-qubit systems. We estimate also that for gypsum at room temperature $$Q\sim 10^{-18}$$ Q ~ 10 - 18 bit/dimer, and for 1,2-dichloroethane at $$T=90$$ T = 90 K the discord is $$Q\sim 10^{-17}$$ Q ~ 10 - 17 bit per a dimer.