In the 1970s, Zeilinger worked at the Vienna Atominstitut as a research assistant and later as an associate researcher at the Massachusetts Institute of Technology Neutron Diffraction Laboratory until 1979, when he accepted the position of assistant professor at the same Atominstitut. That year he qualified as a university professor at the Vienna University of Technology.[11][15]
In 1981 Zeilinger returned to MIT, as an associate professor on the physics faculty, until 1983. Between 1980 and 1990 he worked as a professor at the Vienna University of Technology, the Technical University of Munich, the University of Innsbruck and the University of Vienna.[16]
He was also the scientific director of the Institute for Quantum Optics and Quantum Information in Vienna between 2004 and 2013.[11] Zeilinger became professor emeritus at the University of Vienna in 2013.[11] He was president of the Austrian Academy of Sciences from 2013 till 2022.[17]
Since 2006, Zeilinger is the vice chairman of the board of trustees of the Institute of Science and Technology Austria, an ambitious project initiated by Zeilinger's proposal. In 2009, he founded the International Academy Traunkirchen,[18] which is dedicated to the support of gifted students in science and technology. He is a fan of the Hitchhiker's Guide To The Galaxy by Douglas Adams, going so far as to name his sailboat 42.[19]
Research
Quantum teleportation
Zeilinger published one of the first realizations of quantum teleportation of an independent qubit.[20][21] He later expanded this work to developing a source for freely propagating teleported qubits[22] and quantum teleportation over 144 kilometers between two Canary Islands.[23] Quantum teleportation is an essential concept in many quantum information protocols. Besides its role for the transfer of quantum information, it is also considered as an important possible mechanism for building gates within quantum computers.[24]
Entanglement swapping – teleportation of entanglement
Entanglement swapping is the teleportation of an entangled state. After its proposal,[25] entanglement swapping was first realized experimentally by Zeilinger's group in 1998.[26] It was then applied to carry out a delayed-choice entanglement swapping test.[27]
Entanglement beyond two qubits – GHZ-states and their realizations
Anton Zeilinger contributed to the opening up of the field of multi-particle entanglement.[28] In 1990, he was the first with Daniel Greenberger and Michael Horne to work on entanglement of more than two qubits.[29] The resulting GHZ theorem (see Greenberger–Horne–Zeilinger state) is fundamental for quantum physics, as it provides the most succinct contradiction between local realism and the predictions of quantum mechanics.[30]
GHZ states were the first instances of multi-particle entanglement ever investigated.[31]
Finally, in 1999, he succeeded in providing the first experimental evidence of entanglement beyond two particles[32] and also the first test of quantum nonlocality for GHZ states.[33]
In 1998 (published in 2000), his group was the first to implement quantum cryptography with entangled photons.[34][35] He then applied quantum entanglement to optical quantum computation, where in 2005,[36] he performed the first implementation of one-way quantum computation. This is a protocol based on quantum measurement as proposed by Knill, Laflamme and Milburn.[37]
The experiments of Zeilinger and his group on the distribution of entanglement over large distances began with both free-space and fiber-based quantum communication and teleportation between laboratories located on the different sides of the river Danube.[38] This was then extended to larger distances across the city of Vienna[39] and over 144 km between two Canary Islands, resulting in a successful demonstration that quantum communication with satellites is feasible. His dream is to put sources of entangled light onto a satellite in orbit.[19] A first step was achieved during an experiment at the Italian Matera Laser Ranging Observatory [it].[40]
Further novel entangled states
With his group, Anton Zeilinger made many contributions to the realization of novel entangled states. The source for polarization-entangled photon pairs developed with Paul Kwiat when he was a PostDoc in Zeilinger's group[41] is used in many laboratories. The first demonstration of entanglement of orbital angular momentum of photons opened up a new field of research in many laboratories.[42]
Macroscopic quantum superposition
Zeilinger is also interested to extend quantum mechanics into the macroscopic domain. In the early 1990s, he started experiments in the field of atom optics. He developed a number of ways to coherently manipulate atomic beams, many of which, like the coherent energy shift of an atomic De Broglie wave upon diffraction at a time-modulated light wave, have become part of today's ultracold atom experiments. In 1999, Zeilinger abandoned atom optics for experiments with very complex and massive macro-molecules – fullerenes. The successful demonstration of quantum interference for these C60 and C70 molecules[43] in 1999 opened up a very active field of research.
In 2005, Zeilinger with his group investigated the quantum physics of mechanical cantilevers. In the year 2006 along with Heidmann in Paris[citation needed] and Kippenberg in Garching[citation needed] they demonstrated experimentally the self-cooling of a micro-mirror by radiation pressure, that is, without feedback.[44]
Using orbital angular momentum states, he was able to demonstrate entanglement of angular momentum up to 300 ħ.[45]
Further fundamental tests
Zeilinger's program of fundamental tests of quantum mechanics is aimed at implementing experimental realizations of many non-classical features of quantum physics for individual systems. In 1998,[46] he provided the final test of Bell's inequality closing the communication loophole by using superfast random number generators. His group also realized the first Bell inequality experiment implementing the freedom-of-choice condition[47] and provided the first realization of a Bell test without the fair sampling assumption for photons.[48]
Among the further fundamental tests he performed the most notable one is his test of a large class of nonlocal realistic theories proposed by Leggett.[49] The group of theories excluded by that experiment can be classified as those which allow reasonable subdivision of ensembles into sub-ensembles. It goes significantly beyond Bell's theorem. While Bell showed that a theory which is both local and realistic is at variance with quantum mechanics, Leggett considered nonlocal realistic theories where the individual photons are assumed to carry polarization. The resulting Leggett inequality was shown to be violated in the experiments of the Zeilinger group.[50]
In an analogous way, his group showed that even quantum systems where entanglement is not possible exhibit non-classical features which cannot be explained by underlying non-contextual probability distributions.[51]
Neutron interferometry
Anton Zeilinger's earliest work is perhaps his least known. His work on neutron interferometry has provided a foundation for his later research.[52]
As a member of the group of his thesis supervisor, Helmut Rauch, at the Technical University of Vienna, Zeilinger participated in a number of neutron interferometry experiments at the Institut Laue–Langevin (ILL) in Grenoble. His very first such experiment confirmed a fundamental prediction of quantum mechanics, the sign change of a spinor phase upon rotation.[53] This was followed by the first experimental realization of coherent spin superposition of matter waves. He continued his work in neutron interferometry at MIT with C.G. Shull (Nobel Laureate), focusing specifically on dynamical diffraction effects of neutrons in perfect crystals which are due to multi-wave coherent superposition. After his return to Europe, he built up an interferometer for very cold neutrons which preceded later similar experiments with atoms. The fundamental experiments there included a most precise test of the linearity of quantum mechanics. Zeilinger built a double-slit diffraction experiment[54] on the S18 instrument at the Institut Laue-Langevin which, later on, gained in accuracy and could act with only one neutron at a time in the apparatus.[55]
Cozzarelli Prize in Physical and Mathematical Sciences, PNAS and National Academy of Sciences (2018, with Alexey A. Melnikov, Hendrik Poulsen Nautrup, Mario Krenn, Vedran Dunjko, Markus Tiersch and Hans Briegel)[57]
^Barz, Stefanie (15 October 2012). "Photonic Quantum Computing". Archived from the original on 4 October 2022. Retrieved 15 October 2021 – via othes.univie.ac.at.
^"Prof. Dr. Stefanie Barz". Institute for Functional Matter and Quantum Technologies, University of Stuttgart. Archived from the original on 24 October 2021. Retrieved 15 October 2021.
^For a history of Zeilinger's career in the Austrian context of the rise of quantum foundationd and quantum information, see Del Santo, F. and Schwarzhans, E., 2022. “Philosophysics” at the University of Vienna: The (Pre-) History of Foundations of Quantum Physics in the Viennese Cultural Context. Physics in Perspective, 24(2-3), pp.125-153. {cite|url=https://arxiv.org/abs/2011.11969}
^Del Santo, F. and Schwarzhans, E., 2022. “Philosophysics” at the University of Vienna: The (Pre-) History of Foundations of Quantum Physics in the Viennese Cultural Context. Physics in Perspective, 24(2-3), pp.125-153. {cite|url=https://arxiv.org/abs/2011.11969}
^Del Santo, F. and Schwarzhans, E., 2022. “Philosophysics” at the University of Vienna: The (Pre-) History of Foundations of Quantum Physics in the Viennese Cultural Context. Physics in Perspective, 24(2-3), pp.125-153. {cite|url=https://arxiv.org/abs/2011.11969}
^D. Bouwmeester, J. W. Pan, K. Mattle, M. Eibl, H. Weinfurter & A. Zeilinger, Experimental Quantum Teleportation, Nature 390, 575–579 (1997). AbstractArchived 29 October 2009 at the Wayback Machine. Selected for the Nature "Looking Back" category of classic papers from Nature's archive; one of ISI's "Highly Cited Papers".
^J.-W. Pan, S. Gasparoni, M. Aspelmeyer, T. Jennewein & A. Zeilinger, Experimental Realization of Freely Propagating Teleported Qubits, Nature 421, 721–725 (2003). AbstractArchived 15 November 2013 at the Wayback Machine.Selected by the International Institute of Physics as one of the top ten Physics Highlights in 2003.
^X.-S. Ma, T. Herbst, T. Scheidl, D. Wang, S. Kropatschek, W. Naylor, B. Wittmann, A. Mech, J. Kofler, E. Anisimova, V. Makarov, T. Jennewein, R. Ursin & A. Zeilinger, Quantum teleportation over 143 kilometres using active feed-forward, Nature 489, 269–273 (2012). AbstractArchived 4 October 2022 at the Wayback Machine. Ranked as a "highly cited paper" by Thomson Reuters' Web of Science, placing it in the 1% of the academic field of physics based on a highly cited threshold for the field and publication year.
^M. Zukowski, A. Zeilinger, M. A. Horne & A.K. Ekert, Event-Ready-Detectors Bell Experiment via Entanglement Swapping, Phys. Rev. Lett. 71, 4287–90 (1993). Abstract.
^J.-W. Pan, D. Bouwmeester, H. Weinfurter & A. Zeilinger, Experimental entanglement swapping: Entangling photons that never interacted, Phys. Rev. Lett. 80 (18), 3891–3894 (1998). Abstract.
^X.-S. Ma, S.Zotter, J. Kofler, R. Ursin, T. Jennewein, Č. Brukner & A. Zeilinger, Experimental delayed-choice entanglement swapping, Nature Physics 8, 479–484 (2012). AbstractArchived 4 October 2022 at the Wayback Machine.
^D. M. Greenberger, M. A. Horne, A. Shimony & A. Zeilinger, Bell's Theorem without Inequalities, American Journal of Physics 58, 1131–1143 (1990). This paper has become a citation classic.
^Daniel M. Greenberger; Michael A. Horne; Anton Zeilinger (1989). "Going Beyond Bell's Theorem". In Kafatos, Menos (ed.). Bell's Theorem, Quantum Theory, and Conceptions of the Universe (1 ed.). Heidelberg: Springer. pp. 69–72. arXiv:0712.0921. ISBN978-94-017-0849-4.
^D. Bouwmeester, J.-W. Pan, M. Daniell, H. Weinfurter & A. Zeilinger, Observation of three-photon Greenberger–Horne–Zeilinger entanglement, Phys. Rev. Lett. 82 (7), 1345–1349 (1999). AbstractArchived 4 October 2022 at the Wayback Machine.
^J.-W. Pan, D. Bouwmeester, M. Daniell, H. Weinfurter & A. Zeilinger, Experimental test of quantum nonlocality in three-photon Greenberger-Horne-Zeilinger entanglement, Nature 403, 515–519 (2000). AbstractArchived 15 November 2013 at the Wayback Machine.
^T. Jennewein, C. Simon, G. Weihs, H. Weinfurter & A. Zeilinger, Quantum Cryptography with Entangled Photons, Phys. Rev. Lett. 84, 4729–4732 (2000). Abstract. This paper was featured in several popular science magazines, both online and in print.
^Del Santo, F. and Schwarzhans, E., 2022. “Philosophysics” at the University of Vienna: The (Pre-) History of Foundations of Quantum Physics in the Viennese Cultural Context. Physics in Perspective, 24(2-3), pp.125-153. {cite|url=https://arxiv.org/abs/2011.11969}
^P. Walther, K.J. Resch, T. Rudolph, E. Schenck, H. Weinfurter, V. Vedral, M. Aspelmeyer & A. Zeilinger, Experimental one-way quantum computing, Nature 434 (7030), 169–176 (2005). AbstractArchived 4 October 2022 at the Wayback Machine.
^E. Knill, R. Laflamme & G. J. Milburn, A scheme for efficient quantum computation with linear optics, Nature 409, 46–52 (2001). AbstractArchived 14 November 2013 at the Wayback Machine.
^P.G. Kwiat, K. Mattle, H. Weinfurter, A. Zeilinger, A.V. Sergienko & Y.H. Shih, New High-Intensity Source of Polarization-Entangled Photon Pairs, Phys. Rev. Lett. 75 (24), 4337–41 (1995). Abstract.
^A. Mair, A. Vaziri, G. Weihs & A. Zeilinger, Entanglement of the orbital angular momentum states of photons, Nature 412 (6844), 313–316 (2001). AbstractArchived 3 May 2010 at the Wayback Machine.
^M. Arndt, O. Nairz, J. Voss-Andreae, C. Keller, G. van der Zouw & A. Zeilinger, Wave-particle duality of C60 molecules, Nature 401, 680–682 (1999). AbstractArchived 21 September 2012 at the Wayback Machine. Selected by the American Physical Society as a physics highlight of 1999.
^S. Gigan, H. R. Böhm, M. Paternostro, F. Blaser, G. Langer, J. B. Hertzberg, K. Schwab, D. Bäuerle, M. Aspelmeyer & A. Zeilinger, Self-cooling of a micro-mirror by radiation pressure, Nature 444, 67–70 (2006). AbstractArchived 1 August 2013 at the Wayback Machine.
^R. Fickler, R. Lapkiewicz, W. N. Plick, M. Krenn, C. Schäff, S. Ramelow & A. Zeilinger, Quantum entanglement of high angular momenta, Science 338, 640–643 (2012). AbstractArchived 29 December 2021 at the Wayback Machine. Selected as one of the top 10 breakthroughs of the year 2012 by IOP'sPhysics World. Also featured in DPG'sPhysik Journal. Ranked as a "highly cited paper" by Thomson Reuters' Web of Science, placing it in the 1% of the academic field of physics based on a highly cited threshold for the field and publication year.
^G. Weihs, T. Jennewein, C. Simon, H. Weinfurter & A. Zeilinger, Violation of Bell's inequality under strict Einstein locality conditions, Phys. Rev. Lett. 81 (23), 5039–5043 (1998). Abstract. This paper is a classic. It is cited (among others) in the German Wikipedia article on Bell's inequality and in several popular science books and science books for University students.
^T. Scheidl, R. Ursin, J. Kofler, S. Ramelow, X. Ma, T. Herbst, L. Ratschbacher, A. Fedrizzi, N. K. Langford, T. Jennewein & A. Zeilinger, Violation of local realism with freedom of choice, PNAS 107 (46), 19709 – 19713 (2010). Abstract
^A. J. Leggett, Nonlocal Hidden-Variable Theories and Quantum Mechanics: An Incompatibility Theorem, Foundations of Physics 33 (10), 1469–1493 (2003)(doi:10.1023/A:1026096313729) AbstractArchived 4 October 2022 at the Wayback Machine.
^S. Gröblacher, T. Paterek, R. Kaltenbaek, C. Brukner, M. Zukowski, M. Aspelmeyer & A. Zeilinger, An experimental test of non-local realism, Nature 446, 871–875 (2007). AbstractArchived 15 April 2016 at the Wayback Machine.
^R. Lapkiewicz, P. Li, C. Schäff, N. K. Langford, S. Ramelow, M. Wiesniak & A. Zeilinger, Experimental non-classicality of an indivisible quantum system, Nature 474, 490–493 (2011).AbstractArchived 7 September 2011 at the Wayback Machine
^Del Santo, F. and Schwarzhans, E., 2022. “Philosophysics” at the University of Vienna: The (Pre-) History of Foundations of Quantum Physics in the Viennese Cultural Context. Physics in Perspective, 24(2-3), pp.125-153. {cite|url=https://arxiv.org/abs/2011.11969}
^"Stříbrné medaile předsedy Senátu" [Silver medals of the President of the Senate]. Senát PČR (in Czech). 19 September 2022. Archived from the original on 19 September 2022. Retrieved 4 October 2022.
^"Verzeichnis der Mitglieder"(PDF). Pour le mérite für Wissenschaften und Künste. 25 August 2022. p. 48. Archived from the original(PDF) on 6 October 2022. Retrieved 7 October 2022.
^"EOS Prize". European Optical Society. Retrieved 7 October 2022.
The lecture delivered by Professor Anton Zeilinger as the inaugural recipient of the Isaac Newton Medal, Institute of Physics, 17 June 2008, [1] (68 min 25 sec). Note: On the page linked, a second video is accommodated which shows Professor Zeilinger speaking amongst others about his personal life.