• The Theoretical Optics & Photonics group has been honered in "double dose". Julia and Daniel were both awarded with the Lise-Meitner-Preis ​for their PhD and Master thesis. Congratulations to both!!! The award cerimony is at 4 pm on July 21st in the Christian-Gerthsen lecture hall at the Institute of physics of the Humbodlt University.

• The summer semester 2017 officially started on April 18. Francesco and Marty are holding the lecture and the exercises on Fluctuation-induced Phenomena for the fourth time.

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• Daniel's paper on Spatial dispersion in atom-surface quantum friction has been accepted for publication in Physical Review B. Congratulations Daniel!​
  
  Synopsis. The paper discusses in detail  the influence of spatial dispersion on atom-surface quantum friction and shows that for atom-surface separations shorter than the carrier's mean free path within the material, the frictional force can be several orders of magnitude larger than that predicted by local optics. In addition, when taking into account spatial dispersion effects, it shows that the commonly used local thermal equilibrium approximation underestimates by approximately 95% the drag force. Unlike the treatment based on local optics, spatial dispersion in conjunction with corrections to local thermal equilibrium not only change the magnitude but also the distance scaling of quantum friction.

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• Christoph Egerland has officially started his Bachelor thesis on Casimir interactions in graphene systems. Welcome Christoph!

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• Daniel Reiche is now a PhD student of the TO&P group. He will work on the role of material, geometrical and statistics properties in equilibrium  and nonequilibrium fluctuation-induced interactions. Welcome back Daniel!

• The project INPhAS came to his end. In these three years of work the project led to advancement beyond the state of the art in the field of fluctuation-induced interactions. It produced a total of 10 publications in peer-review journals, 7 invited talks, 5 contributed talks and several highlights in scientific outlets. We thank our collaborators for this success!

• ​Prof. Ferdinand Schmidt-Kaler from the Institut für Physik, Johannes Gutenberg-Universität Mainz is guest of the TO&P group. His colloquium on "Quantum optics with trapped ions – from single ion heat engines to ions in vortex laser fields" has several contact points with the thematic treated in the INPhAS project.

• Francesco officially started the procedure for getting his habilitation degree. On January 31st he gave the colloquium "Fluctuation-induced phenomena in equilibrium and nonequilibrium systems" at the Humboldt University of Berlin.

• The second funding period of the INPhAS project was characterized by a relevant outcome on the validity of the local thermal equilibrium approximation in fluctuation-induced interactions. Despite this approximation has been widely used to describe several nonequilibrium systems, it drastically fails in quantum friction. This major result was reported by several scientific outlets and the highlight “Quantum friction - beyond the local equilibrium approximation” appeared  on phys.org.
   

• Francesco gave this moth two invited taks:

1. Role of material properties in equilibrium and non-equilibrium atom-surface interactions. Optikseminar, Universität Rostock, Rostock, Germany. 
2. Equilibrium and Non-Equilibrium Fluctuation-Induced Interactions in multipartite systems. Colloquium of the Collaborative Research Center 925 “Light induced dynamics and control of correlated quantum systems”, Universität Hamburg, Hamburg, Germany.

• ​The paper "Non-Markovianity in atom-surface dispersion forces" has been published on Physical Review A.
  
  Synopsis. The paper discusses the failure of the Markov approximation in the description of atom-surface fluctuation-induced interactions, both in equilibrium (Casimir-Polder forces) and out of equilibrium (quantum friction). Using general theoretical arguments, it is shown that the Markov approximation can lead to erroneous predictions of such phenomena with regard to both strength and functional dependencies on system parameters. In particular, the behavior of the long-time power-law tails of two-time dipole correlations and their corresponding low-frequency behavior, neglected in the Markovian limit, affect the prediction of the force. These findings highlight the importance of non-Markovian effects in dispersion interactions.

• The paper "Failure of Local Thermal Equilibrium in Quantum Friction" has been published on Physical Review Letters.
  
  Synopsis. Recent progress in manipulating atomic and condensed matter systems has instigated a surge of interest in nonequilibrium physics, including many-body dynamics of trapped ultracold atoms and ions, near-field radiative heat transfer, and quantum friction. Under most circumstances the complexity of such nonequilibrium systems requires a number of approximations to make theoretical descriptions tractable. In particular, it is often assumed that spatially separated components of a system thermalize with their immediate surroundings, although the global state of the system is out of equilibrium. This powerful assumption reduces the complexity of nonequilibrium systems to the local application of well-founded equilibrium concepts. While this technique appears to be consistent for the description of some phenomena, we show that it fails for quantum friction by underestimating by approximately 80% the magnitude of the drag force. Our results show that the correlations among the components of driven, but steady-state, quantum systems invalidate the assumption of local thermal equilibrium, calling for a critical reexamination of this approach for describing the physics of nonequilibrium systems.

• Marty Oelschläger is now a PhD student of the TO&P group. He will work on the theory of fluctuation-induced phenomena at nano-photonic systems. Welcome Marty!

• Prof. Ulf Leonhardt from the Weizmann Institute of Science is guest of the TO&P group. In his colloquium on "Cosmology in the laboratory" he discussed several topics related to the INPhAS project.

• ​Francesco gave a talk at the workshop "Casimir and van der Waals physics: Progress and prospects" hosted in the IAS Building at The Hong Kong University of Science and Technology. The workshop's program focuses on recent developments in the fields of Casimir and van der Waals interactions and the prospects of novel applications of these forces. Francesco's presentation on the "Statistical Aspects of Quantum Friction" was recorded and the video appeared on Youtube.

• Daniel was awarded with a fellowship in the framework of PROMOS program funded by the DAAD. Congratulations! ​​

The fellowship will allow him to spend two months at the Los Alamos National Laboratory, New Mexico, USA. There he will collaborate with Diego Dalvit on the topic of his Master thesis.

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• Francesco is among the organizers of the Early Stage Researchers workshop on Nanoscale Quantum Optics. The workshop takes place in La Villette (Malta) on November 15-18 and it is funded by the EU COST Action MP1403. The aim of the workshop is 1) to provide a unique platform for the youngest researchers to familiarize themselves with their colleagues and form long-lasting networks; 2) to allow these researchers the opportunity to formally present their work to an audience of their peers; 3) to help PhD students close to graduation and older ESRs with information about the various (european and other) funding and employment options that are available to them.

• Prof. Dirk Bouwmeester from Leiden University and University of California in Santa Barbara is guest of the TO&P group. In his colloquium on "Knots of light, gravitational waves, and plasma" he discusses systems that are related to the INPhAS project.

• Prof. Lev Pitaevskii from the University of Trento is guest of the TO&P group. His colloquium on "Stress tensor of electromagnetic field in absorbing media and problem of Van der Waals - Casimir forces" has strong contact points with the thematics treated in the INPhAS project.

• The project INPhAS started officially this month. In the next three years of work the project will try to advance the state of the art in the field of fluctuation-induced interactions.