557 research outputs found
Decay and storage of multiparticle entangled states of atoms in collective thermostat
We derive a master equation describing the collective decay of two-level
atoms inside a single mode cavity in the dispersive limit. By considering
atomic decay in the collective thermostat, we found a decoherence-free subspace
of the multiparticle entangled states of the W-like class. We present a scheme
for writing and storing these states in collective thermostat
Quantum discord in spin-cluster materials
The total quantum correlation (discord) in Heisenberg dimers is expressed via
the spin-spin correlation function, internal energy, specific heat or magnetic
susceptibility. This allows one to indirectly measure the discord through
neutron scattering, as well as calorimetric or magnetometric experiments. Using
the available experimental data, we found the discord for a number of binuclear
Heisenberg substances with both antiferro- and ferromagnetic interactions. For
the dimerized antiferromagnet copper nitrate Cu(NO_3)_2*2.5H_2O, the three
independent experimental methods named above lead to a discord of approximately
0.2-0.3 bit/dimer at a temperature of 4 K. We also determined the temperature
behavior of discord for hydrated and anhydrous copper acetates, as well as for
the ferromagnetic binuclear copper acetate complex [Cu_2L(OAc)]*6H_2O, where L
is a ligand.Comment: 7 pages, 6 figure
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