arXiv subjects

Hermann Hessling

Publications and source records attributed to Hermann Hessling.

3 recordsLinked to original sources

arXiv2001

On the Local Equilibrium Principle

A physical system should be in a local equilibrium if it cannot be distinguished from a global equilibrium by ``infinitesimally localized measurements''. This seems to be a natural characterization of local equilibrium, however the problem is to give a precise meaning to the qualitative phrase ``infinitesimally localized measurements''. A solution is suggested in form of a {\em Local Equilibrium Condition} (LEC) which can be applied to non-interacting quanta. The Unruh temperature of massless quanta is derived by applying LEC to an arbitrary point inside the Rindler Wedge. Massless quanta outside a hot sphere are analyzed. A stationary spherically symmetric local equilibrium does only exist according to LEC if the temperature is globally constant. Using LEC a non-trivial stationary local equilibrium is found for rotating massless quanta between two concentric cylinders of different temperatures. This shows that quanta may behave like a fluid with a Bénard instability.

hep-th↗

arXiv1995

On particle--like jets

Under which conditions does a jet appear as a particle--like signal from the hidden realm of quarks and gluons? Motivated by this question jet clustering conditions are formulated, in order to characterize jet clustering algorithms, which can be used for a determination of particle--like jets. Jets are understood as particle--like, if they behave like free particles. The simplest solution to the jet clustering conditions leads to a new jet algorithm: a Lorentz invariant generalization of the JADE algorithm. It is found that this generalization amplifies hadronization effects in certain phase space regions in such a way, that hadronization models might become testable in jet physics at the electron--proton collider HERA. Moreover, a method is suggested, which can be used at HERA, in order to determine a region in the phase space, where hadronization effects from the proton remnant are small and where parton jets are particle--like.

hep-ph↗

arXiv1994

On the Local Equilibrium Condition

A physical system is in local equilibrium if it cannot be distinguished from a global equilibrium by ``infinitesimally localized measurements''. This should be a natural characterization of local equilibrium, but the problem is to give a precise meaning to the qualitative phrase ``infinitesimally localized measurements''. A solution is suggested in form of a Local Equilibrium Condition, which can be applied to linear relativistic quantum field theories but not directly to selfinteracting quantum fields. The concept of local temperature resulting from LEC is compared to an old approach to local temperature based on the principle of maximal entropy. It is shown that the principle of maximal entropy does not always lead to physical states if it is applied to relativistic quantum field theories.

hep-th↗