At the Quantum Optics Center (QUANTOP ) we study quantum effects at lightmatter interface. Particles of light, photons, are great for creating, reading out and transmitting quantum information between material objects.
The Danish Center for Quantum Optics (QUANTOP) was established in 2001 at the Niels Bohr Institute.
 Started as a DNRF "Center of Excellence" QUANTOP’s research is focused on exploring quantum effects at the interface between light and matter.
 Our goal is to develop future quantum technologies based on superposition and entangled states of light and matter.
QUANTOP offers both specialized courses on the bachelor and master level as well as contributing to the overall teaching and research aims of the NBI.
Research at Quantop
At QUANTOP  the Quantum Optics Center – we study quantum effects at lightmatter interface. Particles of light, photons, are great for creating, reading out and transmitting quantum information between material objects.
Quantum mechanics tells us that when light interacts with atoms they can become entangled, that is they exist in quantum superpositions.
Such entanglement, which the founding fathers of quantum mechanics considered its most fundamental and most controversial feature, is used at QUANTOP for breaking established limits in communication and sensing of fields and forces.
Teleportation of quantum states of objects, generation of single photons on demand, quantum memory for light, and measurements of fields and forces beyond the limit set by the Heisenberg uncertainty principle are among the experiments we perform.
Generation of quantum superposition states and entanglement requires extreme control of photons and material objects and careful protection from decoherence caused by the environment.
Various experimental techniques, including lasers, structured fibers, vacuum and cryogenic setups and sensitive electronics have been developed to achieve such control.
Experiments with as diverse objects as room temperature atoms, cold atoms trapped around a nanofiber and highQ mechanical membranes are carried out.
Our goal is to develop future quantum technologies based on superposition and entangled states of light and matter.
The center is funded by an ERC starting grant and DARPA, and the group is world leading in its research fields of quantum optics, atomic physics and optomechanics.
 ERC Grant: INTER FACE
 DARPA: QuASAR
 EU Project: SIQS
 EU Project: MALICIA
 EU Project: IQUOEMS
Publications 1997  today
Phononically shielded photoniccrystal mirror membranes for cavity quantum optomechanics G. Enzian, Z. Wang, A. Simonsen, J. Mathiassen, T. Vibel, Y. Tsaturyan, A. Tagantsev, A. Schliesser and E. S. Polzik Opt. Express Vol. 31 (8) , pp. 13040 (2023) [DOI] 
EntanglementEnhanced Magnetic Induction Tomography W. Zheng, H. Wang, R. Schmieg, A. Oesterle and E. S. Polzik Physical Review Letters Vol. 130 (20) , pp. 203602 (2023) [DOI] 
Twocolour highpurity EinsteinPodolskyRosen photonic state T. B. Brasil, V. Novikov, H. Kerdoncuff, M. Lassen and E. S. Polzik Nature Communications Vol. 13 (1) (2022) [DOI] 
Prospects of a superradiant laser based on a thermal or guided beam of lessmml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"greaterlessmml:mmultiscriptsgreaterlessmml:migreaterSrless/mml:migreaterlessmml:mprescripts /greaterlessmml:none /greaterlessmml:mngreater88less/mml:mngreaterless/mml:mmultiscriptsgreaterless/mml:mathgreater M. Tang, S. A. Schäffer and J. H. Müller Physical Review A Vol. 106 (6) , pp. 063704 (2022) [DOI] 
Trajectories Without Quantum Uncertainties in Composite Systems with Disparate Energy Spectra E. Zeuthen, E. S. Polzik and F. Y. Khalili PRX Quantum Vol. 3 (2) , pp. 020362 (2022) [DOI] 
Roomtemperature singlephoton source with nearmillisecond builtin memory K. B. Dideriksen, R. Schmieg, M. Zugenmaier and E. S. Polzik Nature Communications Vol. 12 (1) (2021) [DOI] 
Highfrequency broadband laser phase noise cancellation using a delay line M. Parniak, I. Galinskiy, T. Zwettler and E. S. Polzik Optics Express Vol. 29 (5) , pp. 6935 (2021) [DOI] 
Dissipative optomechanical coupling with a membrane outside of an optical cavity A. K. Tagantsev and E. S. Polzik Physical Review A Vol. 103 (6) , pp. 063503 (2021) [DOI] 
Cavityimmune spectral features in the pulsed superradiant crossover regime M. Tang, S. A. Schäffer, A. A. Jørgensen, M. R. Henriksen, B. T. R. Christensen, J. H. Müller and J. W. Thomsen Physical Review Research Vol. 3 (3) , pp. 033258 (2021) [DOI] 
Calibration of spinlight coupling by coherently induced Faraday rotation R. A. Thomas, C. Østfeldt, C. Bærentsen, M. Parniak and E. S. Polzik Optics Express Vol. 29 (15) , pp. 23637 (2021) [DOI] 
SinglePhoton Source with NearMillisecond Memory based on RoomTemperature Atomic Vapour M. Zugenmaier, R. Schmieg, K. B. Dideriksen and E. S. Polzik 2021 Conference on Lasers and ElectroOptics Europe &mathsemicolon European Quantum Electronics Conference (CLEO/EuropeEQEC) (2021) [DOI] 
Phonon counting thermometry of an ultracoherent membrane resonator near its motional ground state I. Galinskiy, Y. Tsaturyan, M. Parniak and E. S. Polzik Optica Vol. 7 (6) , pp. 718725 (2020) 
DoubleResonant SumFrequency Generation of Blue Light with NearUnity Quantum Conversion Efficiency H. Kerdoncuff, J. B. Christensen, T. B. Brasil, V. A. Novikov, E. Polzik, J. Hald and M. Lassen Conference on Lasers and ElectroOptics (2020) [DOI] 
Cavityenhanced sumfrequency generation of blue light with nearunity conversion efficiency H. Kerdoncuff, J. B. Christensen, T. B. Brasil, V. A. Novikov, E. S. Polzik, J. Hald and M. Lassen Optics Express Vol. 28 (3) , pp. 3975 (2020) [DOI] 
Measurement and simulation of atomic motion in nanoscale optical trapping potentials S. B. Markussen, J. Appel, C. Østfeldt, J.B. S. Béguin, E. S. Polzik and J. H. Müller Applied Physics B Vol. 126 (4) (2020) [DOI] 
The Copenhagen Conference: Quantum Limits of Knowledge E. S. Polzik Quantum Studies: Mathematics and Foundations Vol. 7 (2) , pp. 195195 (2020) [DOI] 
Entanglement between distant macroscopic mechanical and spin systems R. A. Thomas, M. Parniak, C. Østfeldt, C. B. Møller, C. Bærentsen, Y. Tsaturyan, A. Schliesser, J. Appel, E. Zeuthen and E. S. Polzik Nature Physics Vol. 17 (2) , pp. 228233 (2020) [DOI] 
Detection of lowconductivity objects using eddy current measurements with an optical magnetometer K. Jensen, M. Zugenmaier, J. Arnbak, H. Stærkind, M. V. Balabas and E. S. Polzik Phys. Rev. Research Vol. 1 , pp. 033087 (2019) 
Sensitive optomechanical transduction of electric and magnetic signals to the optical domain A. Simonsen, S. A. Saarinen, J. D. Sanchez, J. H. ArdenkjærLarsen, A. Schliesser and E. S. Polzik Optics Express Vol. 27 (13) , pp. 18561 (2019) [DOI] 
Magnetic resonance imaging with optical preamplification and detection A. Simonsen, J. D. SánchezHeredia, S. A. Saarinen, J. H. ArdenkjærLarsen, A. Schliesser and E. S. Polzik Scientific Reports Vol. 9 (1) (2019) [DOI] 
Gravitational wave detection beyond the standard quantum limit using a negativemass spin system and virtual rigidity E. Zeuthen, E. S. Polzik and F. Y. Khalili Phys. Rev. D Vol. 100 , pp. 062004 (2019) 
Carriermediated optomechanical forces in semiconductor nanomembranes with coupled quantum wells A. Barg, L. Midolo, G. Kirifmmode selse šﬁanskifmmode eelse ėﬁ, P. Tighineanu, T. Pregnolato, A. \c{c}. ç. ifmmode Ielse İﬁmamoifmmode gelse gﬁlu, P. Lodahl, A. Schliesser, S. Stobbe and E. S. Polzik Phys. Rev. B Vol. 98 , pp. 155316 (2018) 
Observation of Quantum Spin Noise in a 1D LightAtoms Quantum Interface J.B. Béguin, J. H. Müller, J. Appel and E. S. Polzik Phys. Rev. X Vol. 8 , pp. 031010 (2018) 
Unconditional SteadyState Entanglement in Macroscopic Hybrid Systems by Coherent Noise Cancellation X. Huang, E. Zeuthen, D. V. Vasilyev, Q. He, K. Hammerer and E. S. Polzik Phys. Rev. Lett. Vol. 121 , pp. 103602 (2018) 
Magnetocardiography on an isolated animal heart with a roomtemperature optically pumped magnetometer K. Jensen, M. A. Skarsfeldt, H. Stærkind, J. Arnbak, M. V. Balabas, S.P. Olesen, B. H. Bentzen and E. S. Polzik Scientific Reports Vol. 8 (1) (2018) [DOI] 
Overcoming the Standard Quantum Limit in Gravitational Wave Detectors Using Spin Systems with a Negative Effective Mass F. Y. Khalili and E. S. Polzik Phys. Rev. Lett. Vol. 121 , pp. 031101 (2018) 
Dissipative versus dispersive coupling in quantum optomechanics: Squeezing ability and stability A. K. Tagantsev, I. V. Sokolov and E. S. Polzik Phys. Rev. A Vol. 97 , pp. 063820 (2018) 
Longlived nonclassical correlations towards quantum communication at room temperature M. Zugenmaier, K. B. Dideriksen, A. S. Sørensen, B. Albrecht and E. S. Polzik Communications Physics Vol. 1 (1) (2018) [DOI] 
Quantum backactionevading measurement of motion in a negative mass reference frame C. B. Møller, R. A. Thomas, G. Vasilakis, E. Zeuthen, Y. Tsaturyan, M. Balabas, K. Jensen, A. Schliesser, K. Hammerer and E. S. Polzik Nature Vol. 547 (7662) , pp. 191195 (2017) [DOI] 
Multimode optomechanical system in the quantum regime W. H. P. Nielsen, Y. Tsaturyan, C. B. Møller, E. S. Polzik and A. Schliesser Proceedings of the National Academy of Sciences Vol. 114 (1) , pp. 6266 (2017) 
Ultracoherent nanomechanical resonators via soft clamping and dissipation dilution Y. Tsaturyan, A. Barg, E. S. Polzik and A. Schliesser Nature Nanotechnology Vol. 12 (8) , pp. 776783 (2017) [DOI] 
Dipole force free optical control and cooling of nanofiber trapped atoms C. Østfeldt, J.B. S. Béguin, F. T. Pedersen, E. S. Polzik, J. H. Müller and J. Appel Opt. Lett. Vol. 42 (21) , pp. 43154318 (2017) 
Scalable photonic network architecture based on motional averaging in room temperature gas J. Borregaard, M. Zugenmaier, J. M. Petersen, H. Shen, G. Vasilakis, K. Jensen, E. S. Polzik and A. S. Sørensen Nature Communications Vol. 7 (1) (2016) [DOI] 
Noninvasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity K. Jensen, R. Budvytyte, R. A. Thomas, T. Wang, A. M. Fuchs, M. V. Balabas, G. Vasilakis, L. D. Mosgaard, H. C. Stærkind, J. H. Müller, T. Heimburg, S.P. Olesen and E. S. Polzik Scientific Reports Vol. 6 (1) (2016) [DOI] 
Entanglement and spin squeezing in a network of distant optical lattice clocks E. S. Polzik and J. Ye Phys. Rev. A Vol. 93 , pp. 021404 (2016) 
Coherent Backscattering of Light Off OneDimensional Atomic Strings H. L. Sørensen, J.B. Béguin, K. W. Kluge, I. Iakoupov, A. S. Sørensen, J. H. Müller, E. S. Polzik and J. Appel Phys. Rev. Lett. Vol. 117 , pp. 133604 (2016) 
A dynamic operation of a PIN photodiode S. Okhonin, M. Gureev, D. Sallin, J. Appel, A. Koukab, A. Kvasov, M. Pastre, E. S. Polzik, A. K. Tagantsev, F. Uddegard and M. Kayal Applied Physics Letters Vol. 106 (3) , pp. 031115 (2015) 
Generation of a squeezed state of an oscillator by stroboscopic backactionevading measurement G. Vasilakis, H. Shen, K. Jensen, M. Balabas, D. Salart, B. Chen and E. S. Polzik Nature Physics Vol. 11 (5) , pp. 389392 (2015) [DOI] 
Optical detection of radio waves through a nanomechanical transducer T. Bağcı, A. Simonsen, S. Schmid, L. Villanueva, E. Zeuthen, J. Appel, J. Taylor, A. Sørensen, K. Usami, A. Schliesser and E. Polzik Nature Vol. 507 , pp. 8185 (2014) 
Generation and Detection of a SubPoissonian Atom Number Distribution in a OneDimensional Optical Lattice J.B. Béguin, E. M. Bookjans, S. L. Christensen, H. L. Sørensen, J. H. Müller, E. S. Polzik and J. Appel Phys. Rev. Lett. Vol. 113 , pp. 263603 (2014) 
Quantum interference of a single spin excitation with a macroscopic atomic ensemble S. Christensen, J.B. Béguin, E. Bookjans, H. Sørensen, J. Müller, J. Appel and E. Polzik Phys. Rev. A Vol. 89 (3) , pp. 033801 (2014) 
Heater selfcalibration technique for shape prediction of fiber tapers H. L. Sørensen, E. S. Polzik and J. Appel J. Lightwave. Technol. Vol. 32 (10) , pp. 18861891 (2014) 
Demonstration of suppressed phonon tunneling losses in phononic bandgap shielded membrane resonators for highQ optomechanics Y. Tsaturyan, A. Barg, A. Simonsen, L. G. Villanueva, S. Schmid, A. Schliesser and E. S. Polzik Optics Express Vol. 22 (6) , pp. 6810 (2014) 
Towards quantum state tomography of a single polariton state of an atomic ensemble S. L. Christensen, J. B. Béguin, H. L. Sørensen, E. Bookjans, D. Oblak, J. H. Müller, J. Appel and E. Polzik New Journal of Physics, Focus issue on Quantum Tomography Vol. 15 (1) , pp. 015002 (2013) 
Deterministic quantum teleportation between distant atomic objects H. Krauter, D. Salart, C. Muschik, J. M. Petersen, H. Shen, T. Fernholz and E. Polzik Nature Physics (2013) 
InSitu DualPort Polarization Contrast Imaging of Faraday Rotation in a High Optical Depth Ultracold 87Rb Atomic Ensemble F. Kaminski, N. Kampel, M. Steenstrup, A. Griesmaier, E. Polzik and J. Müller European Journal of Physics D Vol. 66 , pp. 227 (2012) 
Atomic nonclassicality quasiprobabilities T. Kiesel, W. Vogel, S. Christensen, J.B. Béguin, J. Appel and E. Polzik Phys. Rev. A Vol. 86 , pp. 042108 (2012) 
Evading Quantum Mechanics: Engineering a Classical Subsystem within a Quantum Environment M. Tsang and C. M. Caves Physical Review X Vol. 2 (3) (2012) 
Quantum memory for entangled continuousvariable states K. Jensen, W. Wasilewski, H. Krauter, T. Fernholz, B. Nielsen, M. Owari, M. Plenio, A. Serafini, M. Wolf and E. Polzik Nature Physics Vol. 7 , pp. 1316 (2011) 
Entanglement Generated by Dissipation and Steady State Entanglement of Two Macroscopic Objects H. Krauter, C. Muschik, K. Jensen, W. Wasilewski, J. Petersen, J. Cirac and E. Polzik Phys. Rev. Lett. Vol. 107 (8) , pp. 080503+ (2011) 
Entanglement Generated by Dissipation C. Muschik, H. Krauter, K. Jensen, W. Wasilewski, J. M. Petersen, I. Cirac and E. Polzik International Conference on Quantum Information International Conference on Quantum Information, pp. QMH1 (2011) [URL] 
Fockstate view of weakvalue measurements and implementation with photons and atomic ensembles C. Simon and E. Polzik Phys. Rev. A Vol. 83 (4) , pp. 040101 (2011) 
Mesoscopic Nonclassical Atomic States for Quantum Information and Metrology J. Appel, J. Renema, D. Oblak, A. LouchetChauvet, N. Kjærgaard and E. Polzik (September) Latin America Optics and Photonics Conference (2010) [URL] 
High quality antirelaxation coating material for alkali atom vapor cells M. V. Balabas, K. Jensen, W. Wasilewski, H. Krauter, L. S. Madsen, J. H. Müller, T. Fernholz and E. S. Polzik Opt. Express Vol. 18 (6) , pp. 58255830 (2010) 
Quantum interface between light and atomic ensembles K. Hammerer, A. Sørensen and E. Polzik Rev. Mod. Phys. Vol. 82 , pp. 10411093 (2010) 
Quantum state transfer between light and matter via teleportation H. Krauter, J. Sherson and E. Polzik Laser & Photonics Reviews Vol. 4 (6) , pp. 685696 (2010) [DOI] 
Entanglementassisted atomic clock beyond the projection noise limit A. LouchetChauvet, J. Appel, J. Renema, D. Oblak, N. Kjærgaard and E. Polzik New. J. Phys. Vol. 12 (6) , pp. 065032+ (2010) 
Quantum memories. A review based on the European integrated project `Qubit Applications (QAP)' C. Simon, M. Afzelius, J. Appel, A. Boyer de La Giroday, S. Dewhurst, N. Gisin, C. Hu, F. Jelezko, S. Kröll, J. Müller, J. Nunn, E. Polzik, J. Rarity, H. de Riedmatten, W. Rosenfeld, A. Shields, N. Sköld, R. Stevenson, R. Thew, I. Walmsley, M. Weber, H. Weinfurter, J. Wrachtrup and R. Young European Physical Journal D Vol. 58 , pp. 122 (2010) 
Optoelectronic cooling of mechanical modes in a semiconductor nanomembrane K. Usami, A. Naesby, T. Bagci, B. Nielsen, J. Liu, S. Stobbe, P. Lodahl and E. Polzik (2010) [ArXiv] 
Quantum volume hologram D. Vasilyev, I. Sokolov and E. Polzik Physical Review A Vol. 81 (2) , pp. 020302+ (2010) 
Quantum Noise Limited and EntanglementAssisted Magnetometry W. Wasilewski, K. Jensen, H. Krauter, J. Renema, M. Balabas and E. Polzik Phys. Rev. Lett. Vol. 104 (13) , pp. 133601+ (2010) 
A versatile digital GHz phase lock for external cavity diode lasers J. Appel, A. MacRae and A. Lvovsky Measurement Science and Technology Vol. 20 (5) , pp. 055302+ (2009) 
Mesoscopic atomic entanglement for precision measurements beyond the standard quantum limit J. Appel, P. Windpassinger, D. Oblak, U. Busk Hoff, N. Kjærgaard and E. Polzik P. Natl. Acad. Sci. Vol. 106 , pp. 1096010965 (2009) 
Establishing EinsteinPoldoskyRosen Channels between Nanomechanics and Atomic Ensembles K. Hammerer, M. Aspelmeyer, E. Polzik and P. Zoller Physical Review Letters Vol. 102 (2) , pp. 020501+ (2009) 
Cavityassisted squeezing of a mechanical oscillator K. Jähne, C. Genes, K. Hammerer, M. Wallquist, E. Polzik and P. Zoller Physical Review A Vol. 79 (6) , pp. 063819+ (2009) 
Cancellation of nonlinear Zeeman shifts with light shifts K. Jensen, V. Acosta, J. Higbie, M. Ledbetter, S. Rochester and D. Budker Physical Review A Vol. 79 (2) , pp. 023406+ (2009) 
Polarizationbased lightatom quantum interface with an alloptical trap M. Kubasik, M. Koschorreck, M. Napolitano, S. de Echaniz, H. Crepaz, J. Eschner, E. Polzik and M. Mitchell Physical Review A Vol. 79 (4) , pp. 043815+ (2009) 
Experimental quantum key distribution with proven security against realistic attacks P. Nielsen, C. Schori, J. Sørensen, L. Salvail, I. Damgard and E. Polzik Journal of Modern Optics Vol. 48 (13) , pp. 19211942 (2009) [DOI] 
Quantum polarization spectroscopy of correlations in attractive fermionic gases T. Roscilde, M. Rodríguez, K. Eckert, O. RomeroIsart, M. Lewenstein, E. Polzik and A. Sanpera New Journal of Physics Vol. 11 (5) , pp. 055041+ (2009) 
Spin squeezing of atomic ensembles by multicolor quantum nondemolition measurements M. Saffman, D. Oblak, J. Appel and E. Polzik Phys. Rev. A Vol. 79 (2) , pp. 023831+ (2009) 
Generation of twomode squeezed and entangled light in a single temporal and spatial mode W. Wasilewski, T. Fernholz, K. Jensen, L. Madsen, H. Krauter, C. Muschik and E. Polzik Optics Express Vol. 17 , pp. 14444+ (2009) 
Ultra lownoise differential accoupled photodetector for sensitive pulse detection applications P. Windpassinger, M. Kubasik, M. Koschorreck, A. Boisen, N. Kjærgaard, E. Polzik and J. Müller Measurement Science and Technology Vol. 20 (5) , pp. 055301+ (2009) 
Squeezing of atomic quantum projection noise P. J. Windpassinger, D. Oblak, U. Busk Hoff, A. Louchet, J. Appel, N. Kjaergaard and E. S. Polzik Journal Of Modern Optics Vol. 56 (1819) , pp. 19931998 (2009) 
Quantum nondemolition detection of strongly correlated systems K. Eckert, O. RomeroIsart, M. Rodriguez, M. Lewenstein, E. Polzik and A. Sanpera Nature Physics Vol. 4 , pp. 5054 (2008) 
Spin Squeezing of Atomic Ensembles via NuclearElectronic Spin Entanglement T. Fernholz, H. Krauter, K. Jensen, J. F. Sherson, A. S. Sørensen and E. S. Polzik Phys. Rev. Lett. Vol. 101 (7) , pp. 073601 (2008) [DOI] 
Rayleigh superradiance and dynamic Bragg gratings in an endpumped BoseEinstein condensate A. Hilliard, F. Kaminski, R. Le Targat, C. Olausson, E. Polzik and J. Müller Physical Review A Vol. 78 (5) , pp. 051403+ (2008) 
Quantum Interface between Light and Atomic Ensembles H. Krauter, J. Sherson, K. Jensen, T. Fernholz, J. NeergaardNielsen, B. Nielsen, D. Oblak, P. Windpassinger, N. Kjærgaard, A. Hilliard, C. Olausson, J. Müller and E. Polzik (XVIII) Laser Spectroscopy, pp. 113124 (2008) [URL] 
Detecting entanglement in two mode squeezed states by particle counting C. Muschik, E. Polzik and J. Cirac ArXiv eprints (2008) [ArXiv] 
Echo spectroscopy of atomic dynamics in a Gaussian trap via phase imprints D. Oblak, J. Appel, P. Windpassinger, U. Busk Hoff, N. Kjærgaard and E. Polzik European Physical Journal D Vol. 50 , pp. 6773 (2008) 
Squeezing the limit: quantum benchmarks for the teleportation and storage of squeezed states M. Owari, M. Plenio, E. Polzik, A. Serafini and M. Wolf New Journal of Physics Vol. 10 (11) , pp. 113014+ (2008) 
Quantum physics: The squeeze goes on E. Polzik Nature Vol. 453 , pp. 4546 (2008) [DOI] 
Quantum memory for images: A quantum hologram D. Vasilyev, I. Sokolov and E. Polzik Physical Review A Vol. 77 (2) , pp. 020302+ (2008) 
Inhomogeneous light shift effects on atomic quantum state evolution in nondestructive measurements P. Windpassinger, D. Oblak, U. Busk Hoff, J. Appel, N. Kjærgaard and E. Polzik New. J. Phys. Vol. 10 (5) , pp. 053032+ (2008) 
Nondestructive Probing of Rabi Oscillations on the Cesium Clock Transition near the Standard Quantum Limit P. Windpassinger, D. Oblak, P. Petrov, M. Kubasik, M. Saffman, C. Alzar, J. Appel, J. Müller, N. Kjærgaard and E. Polzik Physical Review Letters Vol. 100 (10) , pp. 103601+ (2008) 
Quantum Polarization Spectroscopy of Ultracold Spinor Gases K. Eckert, Ł. Zawitkowski, A. Sanpera, M. Lewenstein and E. Polzik Physical Review Letters Vol. 98 (10) , pp. 100404+ (2007) 
Spectral theory of quantum memory and entanglement via Raman scattering of light by an atomic ensemble O. Mishina, D. Kupriyanov, J. Müller and E. Polzik Physical Review A Vol. 75 (4) , pp. 042326+ (2007) 
High purity bright single photon source J. NeergaardNielsen, B. Nielsen, H. Takahashi, A. Vistnes and E. Polzik Optics Express Vol. 15 , pp. 79407949 (2007) 
Nondestructive interferometric characterization of an optical dipole trap P. Petrov, D. Oblak, C. Alzar, N. Kjærgaard and E. Polzik Physical Review A Vol. 75 (3) , pp. 033803+ (2007) 
Singlepassage readout of atomic quantum memory J. Fiurášek, J. Sherson, T. Opatrný and E. Polzik Physical Review A Vol. 73 (2) , pp. 022331+ (2006) 
Highfidelity teleportation between light and atoms K. Hammerer, E. S. Polzik and J. I. Cirac Physical Review A Vol. 74 (6) , pp. 064301 (2006) [DOI] 
Macroscopic quantum information channel via the polarizationsensitive interaction between the light and spin subsystems O. Mishina, E. Polzik and D. Kupriyanov Vol. 199 Quantum information processing from theory to experiment, pp. 346352 (2006) 
Efficient quantum memory and entanglement between light and an atomic ensemble using magnetic fields C. Muschik, K. Hammerer, E. Polzik and J. Cirac Physical Review A Vol. 73 (6) , pp. 062329+ (2006) 
Generation of a Superposition of Odd Photon Number States for Quantum Information Networks J. S. NeergaardNielsen, B. M. Nielsen, C. Hettich, K. Mølmer and E. S. Polzik Phys. Rev. Lett. Vol. 97 (8) , pp. 083604 (2006) [DOI] 
Deterministic AtomLight Quantum Interface J. Sherson, B. Julsgaard and E. S. Polzik Vol. 54 Advances In Atomic, Molecular, and Optical Physics, pp. 81130 (2006) 
Light qubit storage and retrieval using macroscopic atomic ensembles J. Sherson, A. Sørensen, J. Fiurášek, K. Mølmer and E. Polzik Physical Review A Vol. 74 (1) , pp. 011802+ (2006) 
Quantum teleportation between light and matter J. F. Sherson, H. Krauter, R. K. Olsson, B. Julsgaard, K. Hammerer, I. Cirac and E. S. Polzik Nature Vol. 443 , pp. 557560 (2006) [DOI] 
Conditions for spin squeezing in a cold^87Rb ensemble S. de Echaniz, M. Mitchell, M. Kubasik, M. Koschorreck, H. Crepaz, J. Eschner and E. Polzik Journal of Optics B: Quantum and Semiclassical Optics Vol. 7 , pp. 548+ (2005) 
Teleportation and spin squeezing utilizing multimode entanglement of light with atoms K. Hammerer, E. Polzik and J. Cirac Physical Review A Vol. 72 (5) , pp. 052313+ (2005) 
Quantum Benchmark for Storage and Transmission of Coherent States K. Hammerer, M. M. Wolf, E. S. Polzik and J. I. Cirac Physical Review Letters Vol. 94 (15) , pp. 150503 (2005) [DOI] 
Multimode entanglement of light and atomic ensembles via offresonant coherent forward scattering D. Kupriyanov, O. Mishina, I. Sokolov, B. Julsgaard and E. Polzik Physical Review A Vol. 71 (3) , pp. 032348+ (2005) 
Diffraction effects on lightatomicensemble quantum interface J. Müller, P. Petrov, D. Oblak, C. Garrido Alzar, S. de Echaniz and E. Polzik Phys. Rev. A Vol. 71 (3) , pp. 033803+ (2005) 
Quantumnoiselimited interferometric measurement of atomic noise: Towards spin squeezing on the Cs clock transition D. Oblak, P. Petrov, C. Garrido Alzar, W. Tittel, A. Vershovski, J. Mikkelsen, J. Sørensen and E. Polzik Physical Review A Vol. 71 (4) , pp. 043807+ (2005) [DOI] 
Quantum interface between light and atomic ensembles E. Polzik and J. Fiurášek Lectures on Quantum Information, pp. 515534 (2005) 
Distant entanglement of macroscopic gas samples J. Sherson, B. Julsgaard and E. Polzik Decoherence, Entanglement and Information Protection in Complex Quantum Systems Vol. 189 (V) Decoherence, Entanglement and Information Protection in Complex Quantum Systems, pp. 353372 (2005) 
Quantum information processing and communication. Strategic report on current status, visions and goals for research in Europe P. Zoller, T. Beth, D. Binosi, R. Blatt, H. Briegel, D. Bruss, T. Calarco, J. Cirac, D. Deutsch, J. Eisert, A. Ekert, C. Fabre, N. Gisin, P. Grangiere, M. Grassl, S. Haroche, A. Imamoglu, A. Karlson, J. Kempe, L. Kouwenhoven, S. Kröll, G. Leuchs, M. Lewenstein, D. Loss, N. Lütkenhaus, S. Massar, J. Mooij, M. Plenio, E. Polzik, S. Popescu, G. Rempe, A. Sergienko, D. Suter, J. Twamley, G. Wendin, R. Werner, A. Winter, J. Wrachtrup and A. Zeilinger European Physical Journal D Vol. 36 , pp. 203228 (2005) [DOI] 
Quantum Cloning of a Coherent Light State into an Atomic Quantum Memory J. Fiurášek, N. Cerf and E. Polzik Physical Review Letters Vol. 93 (18) , pp. 180501+ (2004) 
Lightmatter quantum interface K. Hammerer, K. Mølmer, E. Polzik and J. Cirac Physical Review A Vol. 70 (4) , pp. 044304+ (2004) 
Experimental demonstration of quantum memory for light B. Julsgaard, J. Sherson, J. I. Cirac, J. Fiurášek and E. S. Polzik Nature Vol. 432 , pp. 482486 (2004) [DOI] 
Characterizing the spin state of an atomic ensemble using the magnetooptical resonance method B. Julsgaard, J. Sherson, J. Sørensen and E. Polzik Journal of Optics B: Quantum and Semiclassical Optics Vol. 6 , pp. 514 (2004) 
Atomic spins as a storage medium for quantum fluctuations of light B. Julsgaard, C. Schori, J. L. Sørensen and E. S. Polzik Quantum Info. Comput. Vol. 3 , pp. 518534 (2003) [URL] 
Generating a Superposition of Spin States in an Atomic Ensemble S. Massar and E. Polzik Physical Review Letters Vol. 91 (6) , pp. 060401+ (2003) 
Entanglement and quantum teleportation with multiatom ensembles E. Polzik, B. Julsgaard and J. Sherson Royal Society of London Philosophical Transactions Series A Vol. 361 , pp. 13911399 (2003) [DOI] 
Quantum limits encountered in atomic spin measurements J. Sørensen, B. Julsgaard, C. Schori and E. S. Polzik Spectrochimica Acta Vol. 58 , pp. 9991010 (2003) [DOI] 
Quantum Noise Limited Laser Probing of Atomic Spin States J. Sørensen, B. Julsgaard, C. Schori, J. Hald and E. Polzik Laser Physics Vol. 13 (3) , pp. 359367 (2003) 
Atomic entanglement on a grand scale E. Polzik Physics World Vol. 15 (9) , pp. 3337 (2002) [URL] 
Recording Quantum Properties of Light in a LongLived Atomic Spin State: Towards Quantum Memory C. Schori, B. Julsgaard, J. Sørensen and E. Polzik Physical Review Letters Vol. 89 (5) , pp. 057903+ (2002) 
Narrowband frequency tunable light source of continuous quadrature entanglement C. Schori, J. Sørensen and E. Polzik Physical Review A Vol. 66 (3) , pp. 033802+ (2002) 
Mapping a quantum state of light onto atoms J. Hald and E. Polzik Journal of Optics B: Quantum and Semiclassical Optics Vol. 3 , pp. 83+ (2001) [DOI] 
Experimental longlived entanglement of two macroscopic objects B. Julsgaard, A. Kozhekin and E. S. Polzik Nature Vol. 413 , pp. 400403 (2001) [DOI] 
Quantum Communication between Atomic Ensembles Using Coherent Light L.M. Duan, J. Cirac, P. Zoller and E. Polzik Physical Review Letters Vol. 85 , pp. 56435646 (2000) 
Entanglement transfer from light to atoms J. Hald, J. L. Sørensen, C. Schori and E. S. Polzik Journal of Modern Optics Vol. 47 (1415) , pp. 2000 (2000) [DOI] 
Quantum memory for light A. E. Kozhekin, K. Mølmer and E. Polzik Physical Review A Vol. 62 (3) , pp. 033809 (2000) [DOI] 
Atomic Quantum State Teleportation and Swapping A. Kuzmich and E. Polzik Physical Review Letters Vol. 85 , pp. 56395642 (2000) 
Spin Squeezed Atoms: A Macroscopic Entangled Ensemble Created by Light J. Hald, J. L. Sørensen, C. Schori and E. S. Polzik Phys. Rev. Lett. Vol. 83 (7) , pp. 13191322 (1999) [DOI] 
EinsteinPodolskyRosencorrelated atomic ensembles E. Polzik Physical Review A Vol. 59 , pp. 42024205 (1999) [DOI] 
Unconditional Quantum Teleportation A. Furusawa, J. Sørensen, S. Braunstein, C. Fuchs, H. Kimble and E. Polzik Science Vol. 282 , pp. 706+ (1998) [DOI] 
Quantum Noise of an Atomic Spin Polarization Measurement J. Sørensen, J. Hald and E. Polzik Physical Review Letters Vol. 80 , pp. 34873490 (1998) [DOI] 
Spin Squeezing in an Ensemble of Atoms Illuminated with Squeezed Light A. Kuzmich, K. Mølmer and E. S. Polzik Physical Review Letters Vol. 79 (24) , pp. 47824785 (1997) [DOI] 
We are always looking for motivated and dedicated students with an interest in quantum mechanics, atomic physics, optomechanics, quantum memories laser physics, quantum information.
Please contact Prof. Eugene Polzik at polzik*nbi.dk if you are interested.
 Bachelor Project opportunities
Please contact Prof. Eugene Polzik at polzik*nbi.dk if you are interested.  Master Project opportunities
Please contact Prof. Eugene Polzik at polzik*nbi.dk if you are interested.  PhD positions
Please contact Prof. Eugene Polzik at polzik*nbi.dk if you are interested.  PostDoc positions
Please contact Prof. Eugene Polzik at polzik*nbi.dk if you are interested.
Accommodations
Shortterm accommodation
In case you are making your own arrangements, here is a list including links to nearby hotels and hostels offering private rooms. Please note that the rates are approximate and reflect a single standard rooms with no breakfast included.
Hotel name 
Approx rate

Distance to NBI

Hotel 9 smaa hjem (apartmentstyle) 
800 DKK 
1.0 km 
Hotel Kong Arthur 
1100 DKK 
1.3 km 
Ibsens Hotel 
1000 DKK 
1.3 km 
Generator Hostel 
from 400 DKK 
1.8 km 
Hotel Guldsmeden Babette 
1100 DKK 
1.2 km 
Hotel Guldsmeden Carlton 
1100 DKK 
3.0 km 
CabInn Express 
800 DKK 
3.0 km 
We have also had good experiences with AirBnB for rooms or full apartments  if you go that route, note that Nørrebro (Copehnagen N), Østerbro (Copenhagen Ø) and Copenhagen City/downtown are the neighborhoods closest to the NBI, though any Copenhagen or Frederiksberg address will be close on bike or public transport.
Apartments and other longerterm accomodation
If you are coming with family or staying more than a few days and are interested in renting an apartment or would like to stay in a university student Kollegium (studio apartment), let us know, and we will advise on the possibilities. If you are a new staff member moving to Copenhagen, consult the University Housing Foundation for help, and feel free to let us know if you need further assistance.
The Niels Bohr institute has many M.Sc. and PhD students. The students are closely attached to the research groups and supervisor, and have many social activities for International and Danish students.
If you are interested in studying Quantum Optics, consider looking at these pages:
QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen Ø. Denmark.
Director:
Prof. Eugene Polzik
Office phone: 3532 5424
Cell phone: 2338 2045
Email: polzik@nbi.dk
Charlotte Hviid
Office: Bygning T, Ta2a
Office phone: +45 35325254
Email: hviid@nbi.ku.dk
General information  News in English  The University 
Researchers
Name  Title  Phone  

Search in Name  Search in Title  Search in Phone  
Zoumis, Alkiviadis  PhD Fellow  
Grimaldi, Andrea  Postdoc Marie Curie  +4535332877  
Meng, Chao  Postdoc  +4535337203  
Hviid, Charlotte  Special Consultant  +4535325254  
Zeuthen, Emil  Associate Professor  +4535330276  
Stærkind, Hans  Postdoc  +4535325386  
Galinskiy, Ivan  Research Consultant  
Hansen, Jacob Thornfeldt  Research Assistant  +4535337919  
Béguin, JeanBaptiste Sylvain  Assistant Professor  +4535334116  
Jia, Jun  Postdoc  
Müller, Jörg Helge  Associate Professor  +4535325304  
Pio, Ludvig Andreas  Student  +4535329110  
Balabas, Mikhail Vladlenovich  Special Consultant  +4535329141  
Larsen, Nikolaj Aagaard  PhD Fellow  
Malek Zadeh, Peyman  Research Assistant  
Fedorov, Sergey  Postdoc  
Brito Brasil, Tulio  Assistant Professor  
Novikov, Valerii  Postdoc 