Quantum phase transition between topological orders induced by pairing fermions (Dr. A. Sterdyniak) / Exploring novel routes to early cancer detection: Molecular fingerprinting by field-resolved spectroscopy (Dr. M. Zigman & Dr. I. Pupeza)

  • Double Feature
  • Datum: 12.12.2017
  • Uhrzeit: 14:30 - 15:30
  • Vortragender: Dr. Antoine Stedyniak, PostDoc, Theorie / Dr. Mihaela Zigman & Dr. Ioachim Pupeza, Wissenschaftler, LAP
  • Raum: New Lecture Hall, Room B 0.32
  • Gastgeber: MPQ

Quantum phase transition between topological orders induced by pairing fermions (Dr. A. Sterdyniak)

The discovery of the fractional quantum Hall effect (FQHE) in the 1980s constituted the first observation of a strongly interacting topological phase. These are still at the center of current research both in an effort to find experimental realizations outside of semi-conductor physics and as they serve as building blocks of more exotic phases. In this talk, I will explore a new way to create a bosonic FQH state starting from a fermionic system using pairing interactions that can be engineered using Feshbach resonances. Starting from the non-interacting case where each spin population is prepared in an integer quantum Hall state with unit filling, we follow the evolution of the system as the interaction strength is increased. Above a critical value and for sufficiently low flux density, we observe the emergence of a quasi two-fold degenerate groundstate, which is shown to be the bosonic 1/2 Laughlin state using entanglement spectrum. Our work therefore provides compelling evidence of a topological phase ransition from a fermionic quantum Hall state to the bosonic Laughlin state at a critical attraction strength. This shows that cold atomic gases offer unequaled possibilities to explore phase transitions between topological orders.


Exploring novel routes to early cancer detection: Molecular fingerprinting by field-resolved spectroscopy (Dr. M. Zigman & Dr. I. Pupeza)

At the crossroads of laser physics and molecular medicine we pursue molecular spectroscopy for highly sensitive detection of organic molecules in solution, specially tailored for cancer detection in humans. The approach is label-free, retrieving “global” molecular fingerprints demarcating overall physiological phenotypes based on blood biopsies. For the first time, molecular fingerprinting is based on recording coherent mid-infrared (MIR) electric fields emitted by impulsively excited vibrations of the constituent molecules, as the most fundamental ensemble-integrated measurable consequence of coherently oscillating, sample-specific, microscopic electric dipoles.

Dr. Ioachim Pupeza, laser physicist, is developing powerful broadband femtosecond infrared laser sources along with field-resolving, time-domain metrology for vibrational spectroscopy, and Dr. Mihaela Zigman, molecular cell biologist, is devising experimental paradigms to assess clinical cancer detection to provide robust molecular, cellular and metabolic snapshots characteristic of even the earliest cancer-specific pathological transitions in the human body.

It is the unique combination of laser-based technologies and molecular paradigms that may widen our quantitative understanding of fundamental principles in cancer biology and contribute to real-world cancer diagnostics that will be presented at the talk.

 
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