Europhys. Lett.
Volume 70, Number 5, June 2005
Page(s) 579 - 585
Section General
Published online 29 April 2005
Europhys. Lett., 70 (5), pp. 579-585 (2005)
DOI: 10.1209/epl/i2004-10518-5

Measurable consequences of the local breakdown of the concept of temperature

M. Hartmann1, 2 and G. Mahler2

1  Institute of Thechnical Physics, DLR Stuttgart Pfaffenwaldring 38-40, D-70569 Stuttgart, Germany
2  Institute of Theoretical Physics I, University of Stuttgart Pfaffenwaldring 57, D-70550 Stuttgart, Germany

received 22 October 2004; accepted in final form 13 April 2005
published online 29 April 2005

Local temperature defined by a local canonical state of the respective subsystem, does not always exist in quantum many-body systems. Here, we give some examples of how this breakdown of the temperature concept on small length scales might be observed in experiments: Measurements of magnetic properties of an anti-ferromagnetic spin-1 chain. We show that those magnetic properties are in fact strictly local. As a consequence, their measurement reveals whether the local (reduced) state can be thermal. If it is, a temperature may be associated to the measurement results, while this would lead to inconsistencies otherwise.

05.30.-d - Quantum statistical mechanics.
65.80.+n - Thermal properties of small particles, nanocrystals, nanotubes.
03.67.Mn - Entanglement production, characterization and manipulation.

© EDP Sciences 2005