Robert Weis

Kirchhoff Institute for Physics

The Kirchhoff Institute for Physics (KIP) is named after a prominent physicist of the 19th Century: Gustav Robert Kirchhoff, who worked in Heidelberg for 21 years. His well-known lectures on experimental and theoretical physics attracted many students. Kirchhoff's ground-breaking research was extraordinarily diverse, spanning electrical, magnetic, optical, elastic, hydrodynamic and thermal processes. His laws for electrical circuits are well-known. At the time he was in Heidelberg, in conjunction with Robert Wilhelm Bunsen, he discovered spectral analysis and its application to solar radiation. In this way, Kirchhoff laid the foundation for modern astrophysics, as well as formulating the laws of thermal radiation, which played a key role in the discovery of quantum physics. The KIP aims to continue in this tradition of diverse scientific research and education.

Physikalisches Kolloquium

16. May 2025 5:00 pm  High and Ultra-High-Energy Neutrinos: Cosmic Accelerators, Black Holes and Quantum Imprints

Prof. Dr. Elisa Resconi, TUM School of Natural Sciences, Technische Universität München ,High and ultrahigh energy neutrinos provide a unique window into the most extreme environments in the Universe. Produced in powerful cosmic accelerators such as active galactic nuclei, these elusive particles traverse vast cosmic distances and reach Earth unharmed by magnetic fields or matter. In this talk, we explore how neutrinos act as messengers from supermassive black holes, revealing the physical conditions and processes in their vicinity. We also consider how their observation, in combination with other messengers, may provide subtle clues to the intimate nature of gravity at the quantum level.more...

News

CQD special seminar, 19.5.25, KIP SR. 02403, given by Victor Gondret, Université Paris-Saclay

Next CQD special seminar will be given by Victor Gondret, Université Paris-Saclay
 

Please note the special place and time: 

When: Monday, the 19th of May, 16:00 p.m.,

Where: KIP, INF 227, SR 2403

He will talk about:

Quasi-particle entanglement in a Bose-Einstein condensate : an acoustic analog of the Dynamical Casimir Effect

Parametric resonance is a recurrent phenomenon in physics, observable at all scales. For example, the vibration of a mirror in a cavity leads to the production of photons, a phenomenon known as the dynamical Casimir effect. In 1831, Faraday observed that a container of water excited vertically in a sinusoidal manner generates patterns with a frequency that is half of the excitation frequency. In the primordial universe, after inflation, parametric oscillations of a field (the inflaton) led to the creation of particles from vacuum, whose thermalization subsequently gave rise to the hot, dense state often associated with the Big Bang.

The growth in the number of quasi-particles (or particles) in the excited mode(s) is triggered by the system’s fluctuations and, due to momentum conservation, quasi-particles are created in pairs in two modes of opposite momentum. At zero temperature, quantum fluctuations initiate this growth, but when the temperature is non-zero, both thermal and quantum fluctuations trigger the growth. In this case, the characteristic signature of quantum vacuum fluctuations is then carried by the entanglement between these modes.

In this seminar, I will report on the experimental observation of the growth and decay of quasi-particle in a  parametrically excited Bose-Einstein condensate. I will also discuss the evolution of two-mode entanglement between the quasi-particles and its subsequent disappearance due to thermalization but also effect beyond Bogolyubov theory.

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Spring is coming!

Butterfly-shaped coordination clusters provide an ideal testbed to study fundamental magnetic properties of mixed lnthanide-transition metal systems. In our recent work, we have added a new family of butterfly-structured molecular magnets to this exciting field...

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