bremen will be the main hub for the recently granted graduiertenschule involving the univeristies in bremen, north bremen (Jacobs), oldenburg, and the max planck institute in hamburg. the aim of the program
is research and education in the field of a new class of materials whose macroscopic properties are defined by design and manipulation on a microscopic scale. a prominent example are atomically
thin layers of transition-metal dichalcogenides, such as MoS_{2} or WSe_{2}, which are direct semiconductors with exceptionally large coulomb effects. in the graduate school, i am one out of 12 subproject leaders. more
information on the web page http://www.rtg-qm3.de/

our theoretical work on superradiance (link to phys. rev. applied) in quantum-dot nanolasers is an extension to conventional laser models. together with researches from the universities magdeburg, dortmund, and würzburg, a combined theoretical and experimental work has recently been published in nature communications. you can find the press release here. here.

miniaturisation towards the ultimate limit of cavity-QED can fundamentally change the properties of a laser. in this regime, few solid state emitters or, in the extreme case even a single one, interact with the individual particles of light. how to identify and characterise the emission of such systems is the topic of our work in light: science&publications publised by nature.

you can download my list of scientific contributions here or find my profile on google scholar.

photographs of the FOPS conference, taken place at lake junaluska in august this year, are available as a web gallery.

our latest work on the properties of the single quantum dot laser has appeared in Optics Express

our publication on correlations between single photon-emission events has appeared in **nature**! for a brief summary see the press releases here and here.

micropillar laser, fabricated in the group of Prof. D. Hommel, Univ. Bremen

here is a picture of the campus in bremen.

photographs from the rietzlern workshop in 2008 can be found here!

journey to cuba: plmcn7 conference

in april 2007 I went to Havana to participate in the conference "physics of light-matter interaction in semiconductor nanostructures". the trip was combined with a short holiday, so check out the photographs of this nice spot by clicking here! Before you do, please press
bremen

academic path

publications

talks

posters

thesis

2d materials

quantum dots and microcavity lasers

bose-einstein-condensation

work related friends and sites

Group page of Prof. Jan Wiersig, Otto-von-Guericke Universität Magdeburg

ITP - Institut für Theoretische Physik an der Universität Bremen

AG Jahnke - our semiconductor theory group page

ITP - Institut für Theoretische Physik an der Universität Bremen

Page of the Otago BEC group

Numerical Recipes online

my doctorate work was focussed on the quantum-optical properties of semiconductor nanostructures, where the emission can be strongly shaped by fluctuations and non-classical effects. we have developed and applied theoretical models that combine quantum-optical approaches and tools, such as second-order coherence, with a material-realistic description of semiconductor quantum-dot gain media. a strong emphasis of my work has been the description of quantum-dot nanolasers.

my **PhD thesis** "Theory for Light-Matter Interaction in Semiconductor Quantum Dots" can be found here and is free to download. please drop me a line if it is of any help or inspiration for you!

i did the work towards my master's degree at the university of otago in new zealand. we investigated the properties of ultracold bose gases confined to a two- dimensional geometry. if you are interested in this topic, you can download my msc thesis below.

*Hartree-Fock-Bogoliubov treatment of the two-dimensional trapped Bose gas*, a thesis submitted for the degree Master of Science at the University of Otago, May 2004.

currently i am working as a researcher at the institute for theoretical physics at the univeristy of bremen. i am a member of Frank Jahnkes group (group homepage) and will be related
to the upcoming graduate school on quanum-mechanical materials modeling starting january 2017.

i can be found or contacted here:

...

Dr. Christopher Gies | |

Institut für Theoretische Physik | |

Universität Bremen | Room # o-3120 |

Postfach 330 440 | Tel. +49 (0)421 218-62052 |

28334 Bremen, Germany | Fax. +49 (0)421 218-4869 |

{

}

My main research interest is the theoretical modelling of semiconductor nanostructures at the intersection of solid state physics and quantum optics. I specialize in many-body methods that allow understanding and predicting physical phenomena on the basis of the underlying microscopic processes and correlations. In my work I give great importance to closely collaborating with experimental groups, which is apparent from my publication record. In joint efforts, new phenomena can be unravelled and understood, especially if they arise from correlations and many-body effects in semiconductors.

currently my research focusses on three main topics:

- semiconductor light sources and nanolasers

- two-dimensional semiconductors

- quantum light sources for quantum information technologies

summer 1999 | mechanical engeneering at the Technische Univeristät (TU) Berlin |

1999-2002 | physics studies at the Freie Universität (FU) Berlin |

april 2002 | vordiplom, FU berlin |

2002-2003 | research project work at the Univeristy of Otago, Dunedin, New Zealand |

2003-2004 | Master of Science at the Univeristy of Oago, Dunedin, New Zealand |

november 2004 | doctorate studies with Prof. Frank Jahnke at the Institute for Theoretical Physics, Universität Bremen |

since july 2008 | employment as postdoctorate researcher in the solid state theory group of Prof. Frank Jahnke, Institute for Theoretical Physics, Universität Bremen |

starting january 2017 | project leader in research training group QM^{3} and independent researcher at the Institute for Theoretical Physics, Universität Bremen |

you can download my list of scientific contributions here or find my profile on google scholar.

43. *Nonequilibrium Carrier Dynamics in Transition Metal Dichalcogenide Semiconductors*,
A. Steinhoff, M. Florian, M. Rösner, M. Lorke, T.O. Wehling, C. Gies, and F. Jahnke;
2D Materials **2**, 031006 (2016)

42. *Two-Dimensional Heterojunctions from Nonlocal Manipulations of the Interactions*, M. Rösner, C. Steinke,
M. Lorke, C. Gies, F. Jahnke, and T. O. Wehling; Nano Lett. **16**, 2322 (2016)

41. *Microscopic Theory of Efficient Excitonic Photoluminescence in Direct and Indirect Band Gap Monolayer MoS2*,
A. Steinhoff, J.-H. Kim, F. Jahnke, M. Rösner, D.-S. Kim, C. Lee, G. H. Han, M. S. Jeong, T. O. Wehling, and
C. Gies;
Nano Lett. **15**, 6841 (2015)

40. *Influence of excited carriers on the optical and electronic properties of MoS2*,
A. Steinhoff, M. Rösner, F. Jahnke, T.O. Wehling, and C. Gies;
Nano Lett. **14**, 3743 (2014)

*Coexistence of lasing and strong coupling in quantum-dot microlasers*,
F. Gericke, C. Gies, P. Gartner, S. Holzinger, C. Hopfmann, T. Heindel, J. Wolters, C. Schneider, M. Florian, F.
Jahnke, S. Höfling, M. Kamp, and S. Reitzenstein;
submitted for publication, arXiv:1606.05591

*A few-emitter solid-state multi-exciton laser*,
S. Lichtmannecker, M. Florian, T. Reichert, M. Blauth, M. Bichler, F. Jahnke, J. J. Finley, C. Gies, and M. Kaniber;
submitted for publication, arXiv:1602.03998

39. *Giant photon bunching, superradiant pulse emission and excitation trapping in quantum-dot nanolasers*,
F. Jahnke, C. Gies, M. Aßmann, M. Bayer, H.A.M. Leymann, A. Foerster, J. Wiersig, C. Schneider, M. Kamp,
and S. Höfling;
Nature Communications **7**, 11540 (2016)

38. *Scattering-induced dephasing of multi-exciton transitions in semiconductor quantum dots*,
M. Florian, A. Steinhoff, C. Gies and F. Jahnke; Appl. Phys. B **122**, 1 (2016)

37. *Monolithically integrated high-β GaAs-AlGaAs nanowire lasers on silicon*,
B. Mayer, L. Janker, B. Loitsch, J. Treu, T. Kostenbader, S. Lichtmannecker, T. Reichert, S. Morkötter, M. Kani-
ber, G. Abstreiter, C. Gies, G. Koblmüller and J. J. Finley;
Nano Lett. **16**, 152 (2015)

36. *Sub- and Superradiance in Nanolasers*,
H. A. M. Leymann, A. Foerster, F. Jahnke, J. Wiersig, and C. Gies;
Phys. Rev. Applied **4**, 044018 (2015)

35. *Photon antibunching from few quantum dots in a cavity*,
C. Gies, F. Jahnke, and W. W. Chow; Phys. Rev. A Rapid Communications **91**, 061804(R) (2015)

34. *Correlations between axial and lateral emission of coupled quantum dot micropillar cavities*,
A. Musial, C. Hopfmann, T. Heindel, C. Gies, M. Florian, H. A. M. Leymann, A. Foerster, C. Schneider, S.
Höfling, F. Jahnke, M. Kamp, and S. Reitzenstein;
Phys. Rev. B **91**, 205310 (2015)

33. *Spontaneous, collective coherence in driven, dissipative cavity arrays*,
J. Ruiz-Rivas, E. del Valle, C. Gies, P. Gartner, and M. J. Hartmann;
Phys. Rev. A **90**, 033808 (2014)

32. *Emission properties of nanolasers during transition to lasing*,
W. Chow, F. Jahnke, and C. Gies;
Light: Science & Applications **3**, e201 (2014)

31. *Coulomb-assisted cavity feeding in the non-resonant optical emission from a quantum-dot*
M. Florian, P. Gartner, A. Steinhoff, C. Gies, and F. Jahnke; Phys. Rev. B Rapid Communications **89**, 161302(R), 2014

30. *Equation-of-motion technique for finite-size quantum-dot systems: Cluster expansion method revisited*
M. Florian, C. Gies, F. Jahnke, H. A. M. Leymann, and J. Wiersig; Phys. Rev. B **87**, 165306 (2013)

29. *Phonon-mediated off-resonant coupling effects in semiconductor quantum-dot lasers*, M. Florian, P. Gartner, C. Gies, F. Jahnke;
New J. Physics **15**, 035019 (2013)

28. *Strong antibunching from electrically driven devices with long pulses: A regime for quantum-dot single-photon
generation*,
C. Kessler, M. Reischle, F. Hargart, W. Schulz, M. Eichfelder, R. Rossbach, M. Jetter, P. Michler, P. Gartner, M. Florian, C. Gies, F. Jahnke; Phys. Rev. B **86**, 115326 (2012)

27. *Cavity-assisted emission of polarization-entangled photons from biexcitons in quantum dots with fine-structure
splitting*,
S. Schumacher, J. Forstner, A. Zrenner, M. Florian, C. Gies, P. Gartner, F. Jahnke; Opt. Express **20**, 5335 (2012)

26. *Improved antibunching by using high-excitation pulses from a single semiconductor quantum dot - a theoretical
study*, M. Florian, C. Gies, P. Gartner, and F. Jahnke; J. Opt. Soc. Am. B **29**, A31 (2012)

25. *The single quantum dot-laser: Lasing and strong coupling in the high-excitation regime*,
C. Gies, M. Florian, P. Gartner, and F. Jahnke; Optics Express **19**, 14370 (2011).

24. *Direct observation of correlations between individual photon emission events of a microcavity laser*,
J. Wiersig, C. Gies, F. Jahnke, M. Assmann, T. Berstermann, M. Bayer, C. Kistner, S. Reitzenstein, C. Schneider, S. Hofling, A. Forchel, C. Kruse, J. Kalden, and D. Hommel; Nature **460**, 454 (2009).

23. *Quantum Statistical Properties of the Light Emission from Quantum Dots in Microcavities *,
C. Gies, J. Wiersig, and F. Jahnke; invited book chapter in Advances in Single Semiconductor Quantum Dots (Peter Michler Ed.), Springer. ISBN 978-3-540-87445-4 (2009).

22. *Coherence properties and dynamical photon correlations of quantum-dot-based microcavity lasers*,
J. Wiersig, C. Gies, and F. Jahnke; Phys. stat. sol. B **246**, 273 (2009).

21. *Title Intrinsic Non-Exponential Decay of Time-Resolved Photoluminescence from Semiconductor Quantum Dots*,
J. Wiersig, C. Gies, and F. Jahnke; Advances in Solid State Physics **48**, 4891 (2009).

20. *Ultrafast intensity correlation measurements of quantum dot microcavity lasers*,
M. Assmann, T. Berstermann, J. Wiersig, C. Gies, F. Jahnke, C. Kistner, S. Reitzenstein, A. Forchel, M. Bayer; Phys. stat. sol. C **6**, 399 (2009).

19. *Coherence length of high-beta semiconductor microcavity lasers*,
S. Ates, C. Gies, S. M. Ulrich, J. Wiersig, S. Reitzenstein, A. Löffler, A. Forchel, F. Jahnke, and P. Michler; Phys. stat. sol. C **6**, 568 (2009).

18. *Emission Characteristics, Photon Statistics and Coherence Properties of high-beta Semiconductor Micropillar Lasers*,
S. M. Ulrich, S. Ates, P. Michler, C. Gies, J. Wiersig, F. Jahnke, S. Reitzenstein, C. Hofmann, A. Löffler and A. Forchel; Advances in Solid State Physics **47**, 3 (2008).

17. *Output characteristics of pulsed and continuous-wave-excited quantum-dot microcavity lasers *,
C. Gies, J. Wiersig, and F. Jahnke; Phys. Rev. Lett. **101**, 067401 (2008).

16. *Coherence Properties and Photon Statistics of Quantum-Dot based Microcavity Lasers*,
J. Wiersig, C. Gies, S. Ritter, and F. Jahnke; Conference on Lasers and Electro-optics & Quantum Electronics and Laser Science Conference, Vols. 1-93004-3005 (2008).

15. *Influence of the Spontaneous Emission Factor β on the First-Order Coherence of Semiconductor Microcavity Lasers*,
S. Ates, C. Gies, S. M. Ulrich, J. Wiersig, S. Reitzenstein, A. Löffler, A. Forchel, F. Jahnke, and P. Michler; Phys. Rev. B **78**, 155319 (2008).

14. *Avoided resonance crossings and photon statistics in semiconductor microcavity lasers*,
J. Wiersig, C. Gies, M. Lorke, F. Jahnke, and M. Hentschel; in Lasers and Electro-Optics - Pacific Rim, 2007. CLEO/Pacific Rim 2007, p.1 (2007).

13. *Systematic study of carrier correlations in the electron-hole recombination dynamics of quantum dots*,
T. Berstermann, T. Auer, H. Kurtze, M. Schwab, D. R. Yakovlev, and M. Bayer; J. Wiersig, Christopher Gies, and Frank Jahnke; D. Reuter and A. D. Wieck, Phys. Rev. B **76**, 165318 (2007).

12. *A semiconductor theory for quantum-dot microcavity lasers*,
J. Wiersig, C. Gies, M. Lorke, and F. Jahnke; Physics of Semiconductors, **893**, 1125 (2007).

11. *Laser theory for semiconductor quantum dots in microcavities*,
Christopher Gies, Jan Wiersig and Frank Jahnke, Supperlattices and Microstructures (2007), doi:10.1016/j.spmi.2007.06.026

10. *Electronic shell structure and carrier dynamics of high aspect ratio InP single quantum dots*,
Gareth J. Beirne, Matthias Reischle, Robert Roßbach, Wolfgang-Michael Schulz, Michael Jetter, Jan Seebeck, Paul Gartner, Christopher Gies, Frank Jahnke, and Peter Michler, Phys. Rev. B **75**, 195302 (2007).

9. * Photon Statistics of Semiconductor Microcavity Lasers*, S. M. Ulrich, Christopher Gies, S. Ates,
J. Wiersig, S. Reitzenstein, C. Hofmann, A. Löffler, A. Forchel, F. Jahnke, and P. Michler, Phys. Rev. Lett. **98**, 043906 (2007).

8. * Semiconductor model for quantum-dot-based microcavity lasers*, Christopher Gies, Jan Wiersig, Michael Lorke, and Frank Jahnke, Phys. Rev. A **75**, 013803 (2007).

7.* Microscopic Theory of Quantum Dot Luminescence Spectra*, Christopher Gies, Norman Baer, Jan Wiersig, and Frank Jahnke, phys. stat. sol. C **3**, 2385 (2006).

6. * Luminescence of a semiconductor quantum dot system*, Norman Baer, Christopher Gies, Jan Wiersig, and Frank Jahnke, Eur. Phys. J. B **50**, 411 (2006).

5. * Radiative emission dynamics of quantum dots in a single cavity micropillar*, M. Schwab, H. Kurtze, T. Auer, T. Berstermann, M. Bayer, J. Wiersig, N. Baer, C. Gies, F. Jahnke, J. P. Reithmaier, A. Forchel, M. Benyoucef, and P. Michler, Phy. Rev. B **74**, 045323 (2006).

work about lower dimensional bose-einstein-condensates

4. *Finite-temperature theory of the trapped two-dimensional Bose gas*, Christopher Gies, B. P. van Zyl, S. A. Morgan, and D. A. W. Hutchinson, Phys. Rev. A **69**, 023616 (2004).

3. * Coherence properties of the two-dimensional Bose-Einstein condensate*, Christopher Gies and D. A. W. Hutchinson, Phys. Rev. A **70**, 043606 (2004).

2. * Many-body T-matrix of a two-dimensional Bose-Einstein condensate within the Hartree-Fock-Bogoliubov formalism*, Christopher Gies, M. D. Lee, and D. A. W. Hutchinson, J. Phys. B: At. Mol. Opt. Phys. **38**, 1797-1809 (2005).

1. *Ultracold Two-Dimensional Trapped Bose Gases*, D. A. W. Hutchinson, Christopher Gies, S. A. Morgan, M. D. Lee, and B. P. van Zyl, Laser Physics **15(7)**, 1091-1095 (2005).

conference talks

*The Single QD laser -- From Weak To High Excitation*, __Christopher Gies__, M. Florian, P. Gartner, E. Goldmann, A. Steinhoff, K. Schuh and Frank Jahnke. FOPS 2011 at Lake Junaluska, North Carolina, USA, Aug. 1-5, 2011.

*Cavity-QED With a Single Emitter*, __Christopher Gies__, M. Florian, S. Ritter, P. Gartner, and Frank Jahnke. Quantum Optics Workshop, Würzburg, Germany, October 2010.

*Photon Statistics of Quantum-Dot-Based Microcavity Lasers*, __Christopher Gies__, Jan Wiersig, Michael Lorke, and Frank Jahnke. 7th International Conference of the PLMCN (Physics of light-matter coupling in semiconductor nanostructures) series in Havana, Cuba, April 12-17, 2007.

*Quantum Optics Of Semiconductor Quantum Dots*, __Christopher Gies__, Jan Wiersig, Michael Lorke, and Frank Jahnke. DPG Spring Meeting, Regensburg, March 2007.

*Quantum Optics with Quantum Dots in Microcavities*, Christopher Gies. Workshop on Semiconductor Surfaces, Interfaces and Nanostructures, Bremen, January 2007.

*Photon Statistics Of Semiconductor Microcavity Lasers*, __Christopher Gies__, Jan Wiersig, Norman Baer, and Frank Jahnke. Third International Workshop on Quantum Optics in Semiconductor Nanostructures, Würzburg and Rothenburg ob der Tauber, October 2006.

*Theory of Photoluminescence for Semiconductor Quantum
Dots*, __Christopher Gies__, Jan Wiersig, Norman Baer, and Frank Jahnke. DPG Spring Meeting, Dresden, March 2006.

*Microscopic Theory for Luminescence from Quantum-Dot Systems
Application to Time-Resolved Photoluminescence and Laser Theory*, __Christopher Gies__, Norman Baer, Jan Wiersig, and Frank Jahnke. NOEKS VIII, Münster, Feb. 2006.

*Aspects of the Two-Dimensional Bose Gas at Finite Temperatures*, Classical and Quantum Field Day, Physics Department, University of Otago, February 16 and 17, 2004.

*Theory of optical properties for quantum dots in microcavities*,
__Thomas Auer__, Matthias Schwab, Manfred Bayer,
Thorsten Berstermann, Jan Wiersig, Norman Baer,
Christopher Gies, Frank Jahnke, Viktorina Stavarache,
Dirk Reuter, and Andreas Wieck. DPG Spring Meeting, Dresden, March 2006.

*Demonstration of intrinsic non-exponential quantum dot
emission dynamics due to reduced electron-hole correlation*,
__Frank Jahnke__, Jan Wiersig, Norman Baer, Christopher Gies. DPG Spring Meeting, Dresden, March 2006.

*Direct observation of strong photon field fluctuations in high-Q semiconductor
microcavity laser structures*,
__S.M. Ulrich__, S. Reitzenstein, C. Hoffmann, A. Löffler, C. Gies, J. Wiersig, F. Jahnke,
A. Forchel, P. Michler. NOEKS VIII, Münster, Feb. 2006.

*Dependence of the radiative emission dynamics of quantum dots on e-h correlations*,
__T. Auer__, M. Schwab, H. Kurtze, M. Bayer, J. Wiersig, N. Baer, C. Gies, F. Jahnke, V.
Stavarache, D. Reuter, A. Wieck. NOEKS VIII, Münster, Feb. 2006.

*Emission Properties of Quantum-Dot Microcavity Lasers*,
seminar talk, Universität Paderborn, Germany, May 2011.

*Coherence Properties of Quantum-Dot-Based Microcavity Lasers*,
seminar talk, Johannes Kepler Universität (JKU) Linz, Austria, September 2007.

*Quantum Dot Microcavity Lasers*,
__Christopher Gies__, Jan Wiersig, Michael Lorke, and Frank Jahnke. SfB seminar, TU Berlin, December 2006.

*Laser Theories - A New Approach For Quantum-Dot Based Microcavity Lasers*, Solid State Seminar at the Universität Bremen, June 2006.

*Properties of a Two-Dimensional Bose Gas -- A Theoretical Treatment*, Seminar at the
Physics Department, University of Otago, July 2004.

*Coherence Properties of a Two-Dimensional Bose-Einstein-Condensate*, AG Seminar, Universität Bremen, September 2004.

*The Hofstadter Butterfly*, Journal Club, University of Otago, July 2003.

*Oscillations and Damping of Oscillations in Low-temperature BECs*, Journal Club, University of Otago, April 2004.

*Intrinsic non-exponentiality of the exciton radiative decay in zerodimensional
semiconductor structures*, __T. Auer__, T. Berstermann, M. Schwab M. Bayer, J. Wiersig, N. Baer, C. Gies, F. Jahnke, V. Stavarache, D. Reuter, A. Wieck. Quantum Dots 2006, Chamonix, France, May 2006.

*Phase fluctuations in a two-dimensional, harmonically trapped, dilute Bose gas at finite temperatures*, International Conference on Lasers and Spectroscopy (ICOLS) 2003, Cairns, Australia.

*Properties of a two-dimensional Bose gas at ultralow temperatures*, DPG Tagung 2005, Berlin.