Review

Non-Hermitian physics and PT symmetry

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Abstract

In recent years, notions drawn from non-Hermitian physics and parity–time (PT) symmetry have attracted considerable attention. In particular, the realization that the interplay between gain and loss can lead to entirely new and unexpected features has initiated an intense research effort to explore non-Hermitian systems both theoretically and experimentally. Here we review recent progress in this emerging field, and provide an outlook to future directions and developments.

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Acknowledgements

The authors gratefully acknowledge the financial support from NSF CAREER Award (ECCS-1454531), NSF (ECCS-1545804, DMR-1420620, EECS-1757025), AFOSR (FA9550-14-1-0037), ARO (W911NF-16-1-0013, W911NF-17-1-0481), and ONR (N00014-16-1-2640). K.G.M. and S.R. were funded by the European Commission under projects NOLACOME (PIOF 303228), NHQWAVE (MSCA-RISE 691209), and by the Austrian Science Fund (FWF) through Projects No. F25 (SFB IR-ON), No. F49 (SFB NextLite), No. I1142-N27 (GePartWave). K.G.M. was also supported by the European Union Seventh Framework Program (FP7-REGPOT-2012-2013-1) under grant agreement 316165.

Author information

Affiliations

  1. Department of Physics and Henes Center for Quantum Phenomena, Michigan Technological University, Houghton, Michigan 49931, USA

    • Ramy El-Ganainy
  2. Crete Center for Quantum Complexity and Nanotechnology, Physics Department, University of Crete, PO Box 2208, 71003 Heraklion, Greece

    • Konstantinos G. Makris
  3. College of Optics & Photonics-CREOL, University of Central Florida, Orlando, Florida 32816, USA

    • Mercedeh Khajavikhan
    •  & Demetrios N. Christodoulides
  4. Mathematics Department, Florida State University, Tallahassee, Florida 32306, USA

    • Ziad H. Musslimani
  5. Institute for Theoretical Physics, Vienna University of Technology (TU-Wien), A-1040 Vienna, Austria

    • Stefan Rotter

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All authors contributed equally.

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The authors declare no competing financial interests.

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Correspondence to Demetrios N. Christodoulides.