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The Max Planck Institute for Physics is a physics institute in Munich, Germany that specializes in High Energy Physics and Astroparticle physics. It is part of the Max-Planck-Gesellschaft and is also known as the Werner Heisenberg Institute, after its first director in its current location.The founding of the institute traces back to 1914, as an idea from Fritz Haber, Walther Nernst, Max Planck, Emil Warburg, Heinrich Rubens. On October 1, 1917, the institute was officially founded in Berlin as Kaiser-Wilhelm Institut für Physik with Albert Einstein as the first head director. In October 1922, Max von Laue succeeded Einstein as managing director. Einstein gave up his position as a director of the institute in April 1933. In June 1942, Werner Heisenberg took over as managing director.The Institute took part in the German nuclear weapon project in 1939-1943.A year after the end of fighting in Europe in World War II, the institute was moved to Göttingen and renamed the Max Planck Institute for Physics, with Heisenberg continuing as managing director. In 1946, Carl Friedrich von Weizsäcker and Karl Wirtz joined the faculty as the directors for theoretical and experimental physics, respectively.In 1955 the institute made the decision to move to Munich, and soon after began construction of its current building, designed by Sep Ruf. The institute moved into is current location on September 1, 1958 and took on the new name the Max Planck Institute fore Physics and Astrophysics, still with Heisenberg as the managing director. In 1991, the institute was split into the Max Planck Institute for Physics, the Max Planck Institute for Astrophysics and the Max Planck Institute for Extraterrestrial Physics. Wikipedia.

Zhou S.,Max Planck Institute for Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We apply the permutation symmetry S3 to both charged-lepton and neutrino mass matrices, and suggest a useful symmetry-breaking scheme, in which the flavor symmetry is explicitly broken down via S3→Z3→Ø in the charged-lepton sector and via S3→Z2→Ø in the neutrino sector. Such a two-stage breaking scenario is reasonable in the sense that both Z3 and Z2 are the subgroups of S3, while Z3 and Z2 only have a trivial subgroup. In this scenario, we can obtain a relatively large value of the smallest neutrino mixing angle, e.g., θ13≈9°, which is compatible with the recent result from T2K experiment and will be precisely measured in the ongoing Double Chooz and Daya Bay reactor neutrino experiments. Moreover, the maximal atmospheric mixing angle θ23≈45° can also be obtained while the best-fit value of solar mixing angle θ12≈34° is assumed, which cannot be achieved in previous S3 symmetry models. © 2011 Elsevier B.V. Source

Calcagni G.,Max Planck Institute for Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

Despite their diversity, many of the most prominent candidate theories of quantum gravity share the property to be effectively lower-dimensional at small scales. In particular, dimension two plays a fundamental role in the finiteness of these models of Nature. Thus motivated, we entertain the idea that spacetime is a multifractal with integer dimension 4 at large scales, while it is two-dimensional in the ultraviolet. Consequences for particle physics, gravity and cosmology are discussed. © 2011 Elsevier B.V. Source

Stieberger S.,Max Planck Institute for Physics
Physical Review Letters | Year: 2011

We consider the scattering amplitudes of five and six gravitons at tree level in superstring theory. Their power series expansions in the Regge slope α′ are analyzed through the order α ′8 showing some interesting constraints on higher order gravitational couplings in the effective superstring action such as the absence of R5 terms. Furthermore, some transcendentality constraints on the coefficients of the nonvanishing couplings are observed: the absence of zeta values of even weight through the order α′8 like the absence of ζ(2)ζ(3)R6 terms. Our analysis is valid for any superstring background in any space-time dimension, which allows for a conformal field theory description. © 2011 American Physical Society. Source

Pranzetti D.,Max Planck Institute for Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

By reintroducing Lorentz invariance in canonical loop quantum gravity, we define a geometrical notion of temperature for quantum isolated horizons. This is done by demanding that the horizon state satisfying the boundary conditions be a Kubo-Martin-Schwinger state. The exact formula for the temperature can be derived by imposing the reality conditions in the form of the linear simplicity constraints for an imaginary Barbero-Immirzi parameter. Thus, our analysis reveals the connection between the analytic continuation to the Ashtekar self-dual variables and the thermality of the horizon. The horizon thermal equilibrium state can then be used to compute both the entanglement and the Boltzmann entropies. We show that the two provide the same finite answer, which allows us to recover the Bekenstein-Hawking formula in the semiclassical limit. In this way, we shed new light on the microscopic origin of black hole entropy by revealing the equivalence between the near-horizon degrees of freedom entanglement proposal and the state-counting interpretation. The connection with the Connes-Rovelli thermal time proposal for a general relativistic statistical mechanics is worked out. © 2014 American Physical Society. Source

Calcagni G.,Max Planck Institute for Physics
Physical Review Letters | Year: 2010

We propose a field theory which lives in fractal spacetime and is argued to be Lorentz invariant, power-counting renormalizable, ultraviolet finite, and causal. The system flows from an ultraviolet fixed point, where spacetime has Hausdorff dimension 2, to an infrared limit coinciding with a standard four-dimensional field theory. Classically, the fractal world where fields live exchanges energy momentum with the bulk with integer topological dimension. However, the total energy momentum is conserved. We consider the dynamics and the propagator of a scalar field. Implications for quantum gravity, cosmology, and the cosmological constant are discussed. © 2010 The American Physical Society. Source

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