Program summer term 2015

Monday, April 13, 2015, 4:15pm, Hörsaal 28 D 001

Thomas F. Kelly, PhD (CAMECA Instruments, Inc.)

Atomic-Scale Tomography: An Achievable Vision

Joachim Mayer


Our everyday experience of the world is strongly shaped by scientific knowledge. Scientific knowledge is shaped and driven by microscopy, especially down toward the atomic scale. With this perspective, any advance in microscopy is likely to have important impact on our world. One need look no further than the impact that microscopy has had on the development of our knowledge of disease and our ability to prevent and cure it. Given that the 21st century is often considered to be the century of nanotechnology, advances in atomic-scale microscopy are expected to have widespread impact on our science and technology.

Atomic-scale imaging has undergone revolutionary changes in the past two decades. Aberration correctors for  electron microscopes have pushed the imaging capabilities to the sub-Ångstrom scale. Atom probe tomography has been established as a robust tool for three-dimensional atomic-scale characterization. Have we reached a sort of technological plateau in microscopy? In this lecture, I will argue that the next major step in microscopy,  atomic-scale tomography (AST), is within reach. The vision proffered for AST is one where every atom in a structure is recorded with precise positioning in large (billion atoms) three-dimensional images. Some of the  unproven concepts needed to reach this vision will be highlighted and potential solutions will be discussed. A program called the ATOM project that seeks to reach this plateau by the year 2020 will be described.


Monday, April 27, 2015, 4:15pm, Hörsaal 28 D 001

A/Prof. Andrey A. Sukhorukov (Australian National University)

On-chip quantum photonics with coupled nonlinear waveguides

Dmitry Chigrin

Quantum entangled states of several photons can facilitate absolutely secure communications and realization of ultra-fast calculations exceeding the capabilities of any classical computer. These prospects motivate the development of quantum photon sources integrated on an optical chip. This talk will present the theoretical concepts and experimental results on the generation of photon-pair states with reconfigurable quantum entanglement in integrated coupled nonlinear waveguides. The operation of this nonlinear chip involves the simultaneously occurring processes of spontaneous frequency conversion and quantum walks. It will be shown how the nonlinear structures can serve as all-optically reconfigurable sources of various quantum states. Finally, new opportunities and challenges for realization of single-photon conversion will be discussed.


Monday, May 11, 2015, 4:15pm, Hörsaal 28 D 001

Prof. Dr. Albrecht Böhm (RWTH Aachen)

LEP, the large electron-positron storage ring at CERN:
30 years of technology and science !

Host: Christopher Wiebusch


In experimental particle physics two important particles were
discovered: the gluon at DESY and the  heavy bosons Z and W at
CERN. To study these particles and their forces a large
electron-positron collider LEP has been proposed at CERN.
On 13 September 1983 the start of the LEP construction was marked by
ground-breaking ceremony. In the same year the four colloration Aleph,
Delphi, L3 and Opal had presented the detailed proposals of their
detectors. It is not possible in this talk to discuss several
detectors. We choose the L3 detector because the I. and
III. Physikalisches Institut of the RWTH Aachen participated with
strong contribution. We will show many pictures of the building of the
LEP and the L3 detector and  you see the challenge, the hard work and
the sucess.
The first physics run of LEP started on 20 September 1989 and remained
in the range of center of mass of 90 GeV. From the year 1995 onward
the c.m.s. energy would be increased up to 209 GeV and the last run
has been on 2 November 2000.  The measurements at LEP by Aleph,
Delphi, L3 and Opal have led to more than 1000 publications. We can
only mention a few important results such as the precise measurements
of Z and W+, W- and the wide search of the Higgs particle.



Monday, June 1, 2015, 4:15pm, Hörsaal 28 D 001

Prof. Andrea Morello (University of New South Wales, Australia)

Quantum information processing with single atoms in silicon

Hendrik Bluhm


A phosphorus (31P) donor in silicon is, almost literally, equivalent to a hydrogen atom in vacuum. It possesses electron  and nuclear spins 1/2 which act as natural qubits, and the host material can be isotopically purified from other spin species.  I will present the current state-of-the-art in silicon quantum information technologies. The electron [1] and the nuclear [2] spin of individual 31P atoms have been read out [3] and coherently operated with high fidelity [4], and the 31P  nucleus holds the current record for coherence time (35 seconds) in the solid state [5]. The exchange interaction, already  measured in a single donor pair [6], can mediate entangling two-qubit gates [7] without requiring atomically precise donor  placement.  These results show that silicon – the material underpinning modern computing – can be adapted to host quantum information hardware.

[1] J.J. Pla et al., Nature 489, 541 (2012)
[2] J.J. Pla et al., Nature 496, 334 (2013)
[3] A. Morello et al., Nature 467, 687 (2010)
[4] J.T. Muhonen et al., J. Phys: Condens. Matt. 27, 154205 (2015)
[5] J.T. Muhonen et al., Nature Nanotechnology 9, 986 (2014)
[6] J.P. Dehollain et al., Phys. Rev. Lett. 112, 236801 (2014)
[7] R. Kalra et al., Phys. Rev. X 4, 021044 (2014)


Monday, June 15, 2015, 4:15pm, Hörsaal 28 D 001

Prof. Dr. Werner Hofmann (MPI Heidelberg)

The Galaxy in a new light: Gamma-ray astronomy with Cherenkov telescopes


Abstract: Over the last decade, very high energy (VHE) gamma ray astronomy - at photon energies of 100 GeV and beyond - has developed in giant steps, with the number of known cosmic VHE gamma ray sources approaching 200. Systems of large imaging atmospheric Cherenkov telescopes have played a key role in this development. VHE gamma rays cannot be produced in thermal processes but are produced by interactions of high energy particles. Gamma rays trace populations of such particles and enable the cosmic particle accelerators to be imaged and studied. Gamma-ray emitting particles accelerators are ubiquitous in the Galaxy and beyond; accelerators include a variety of galactic and extragalactic objects. Details of the acceleration mechanisms as well as the role high-energy particles play in the evolution of star forming systems and galaxies remain to be fully understood. The presentation will briefly introduce the Cherenkov technique and then discuss some of the key results, concentrating mostly on sources in our Galaxy, as observed with the H.E.S.S. telescopes. This talk will conclude with an outlook towards the Cherenkov Telescope Array CTA, as the next-generation facility for ground-based gamma-ray astronomy.

Henning Gast


Monday, June 29, 2015, 4:15pm, Hörsaal 28 D 001

Kerstin Borras (RWTH Aachen)

The CMS Experiment  - Status and Perspectives

Thomas Hebbeker

The CMS Experiment  - Status and Perspectives Abstract: The European Committee for Future Accelerators organized a workshopfor a Large Hadron Collider, which took place in Aachen in1990. Following in 1994 a Technical Proposal for the CMS Detector, oneof the general purpose experiments, was submitted. The initial startof the LHC happened in 2008 and the data taking continued in Run 1 in2009-2012 with 7-8 TeV center of mass energy.  Now the CMS Experiment surfaces back after the Long Shutdown 1(2013-2014) rejuvenated and with enhanced performance to take thenovel LHC data at 13 TeV.  These data in a new and  unexplored energyregime are opening the window to novel studies and potentialdiscoveries. The Colloquium will briefly describe the way to the first data taking,give highlights from the first Run 1 data and summarize theimprovements implemented in LS1. Just recently the first collisions of protons at the world-recordenergy of 13 TeV have taken place.  CMS has recorded these data andpursues first analyses. The ambitious aims for physics results fromthe Run 2 data are summarized and an outlook for the exciting futurefor the decades up to the year 2035 is given. 




Monday, August 17th, 2015, 4:15pm, Lecture hall 28 D 001

Yifang Wang (Director of IHEP Beijing)

Neutrino Physics @ China

Christopher Wiebusch

Prof. Yifang Wang, the director of the Institute of High Energy Physics (IHEP) Beijing and spokesperson of the JUNO neutrino experiment, will present current status and perspectives of neutrino physics in China.