University of Jena

About: University of Jena is a education organization based out in Jena, Thüringen, Germany. It is known for research contribution in the topics: Laser & Population. The organization has 22198 authors who have published 45159 publications receiving 1401514 citations. The organization is also known as: Friedrich-Schiller-Universität Jena & Friedrich Schiller University Jena.

The Long Persistence of Regional Levels of Entrepreneurship: Germany, 1925–2005

Abstract: Fritsch M. and Wyrwich M. The long persistence of regional levels of entrepreneurship: Germany, 1925–2005, Regional Studies. This paper investigates the persistent levels of self-employment and new business formation in different time periods and under different framework conditions. The analysis shows that regional differences regarding the level of self-employment and new business formation tend to be persistent for periods as long as eighty years, despite abrupt and drastic changes in the political–economic environment. This pronounced persistence demonstrates the existence of regional entrepreneurship culture that tends to have long-lasting effects.

Asymptotic degeneracy of dyonic N=4 string states and black hole entropy

Abstract: It is shown that the asymptotic growth of the microscopic degeneracy of BPS dyons in four-dimensional N = 4 string theory captures the known corrections to the macroscopic entropy of four-dimensional extremal black holes. These corrections are subleading in the limit of large charges and originate both from the presence of interactions in the effective action quadratic in the Riemann tensor and from non-holomorphic terms. The presence of the non-holomorphic corrections and their contribution to the thermodynamic free energy is discussed. It is pointed out that the expression for the macroscopic entropy, written as a function of the dilaton field, is stationary at the horizon by virtue of the attractor equations.

Experimental Signatures of the Quantum Nature of Radiation Reaction in the Field of an Ultraintense Laser

Abstract: Substantial energy loss in an electron beam passing through a high-intensity laser provides clear evidence of the radiation reaction, shedding light on how electrons interact with extreme electromagnetic fields.