physics
recent research
Continuous-variable qubit states
Please have a go with my cv qubit space flight simulator! It is science, it is fun - what can you lose?
Using a squeezed vacuum source and an advanced photon subtraction technique, we succeeded in generating a large range of different superpositions of squeezed vacuum and squeezed single-photon states. These states can be interpreted as qubits with continuous-variable basis states.
The following animation illustrates this qubit space as a Bloch sphere. Each experimentally obtained state is represented by its Wigner function at the location on the Bloch sphere corresponding to its superposition parameters.
I have also developed an interactive applet that allows you to move around in the qubit space and investigate each state in detail. Go to the cv qubit applet here.
academic history
- 1999–2003
- Bachelor studies in physics and mathematics at University of Copenhagen.
- 2003–2005
- Master studies in physics. My thesis work was carried out in the Quantop group at the Niels Bohr Institute, University of Copenhagen.
- 2005–2008
- PhD studies in experimental quantum optics at Quantop under the supervision of Prof. Eugene Polzik.
- March–May 2006
- Research exchange student in the Furusawa laboratory at the University of Tokyo.
- October 2008–
- Limited term researcher (post doc) in the Quantum ICT Group under Masahide Sasaki at NICT (National Institute of Information and Communications Technology) in Koganei, Tokyo.
My theses for download
- Master thesis
- Nonclassical light source for quantum networks [ pdf, 3.4 MB ]
- PhD thesis
- Generation of single photons and Schrödinger kitten states of light [ pdf, 11.2 MB ]
publications
Journal articles
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Photon subtraction from traveling fields - recent experimental demonstrations
- pdf ©NII
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Engineering of optical continuous-variable qubits via displaced photon subtraction: multimode analysis
- pdf ©T&F
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Optical continuous-variable qubit
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Entanglement distillation from Gaussian input states
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Time gating of heralded single photons for atomic memories
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High purity bright single photon source
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Time-gated Einstein-Podolsky-Rosen correlation
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Generation of a superposition of odd photon number states for quantum information networks
In conference proceedings, etc.
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Continuous variable qubit state engineering
- pdf ©AIP
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Quantum interface between light and atomic ensemblesLaser Spectroscopy. Proceedings of the XVIII ICOLS 2007, Eds. L. Hollberg, J. Bergquist, M. Kasevich, World Scientific (2008)
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Narrow bandwidth optical Schrödinger kitten states and single photonsProceedings of the 8th International Conference on QCMC 2006, Eds. O. Hirota, J. H. Shapiro, and M. Sasaki (2007)
Other appearances
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Bridging discrete and continuous variables in quantum informationOptics in 2010 special issue that "highlights the most exciting peer-reviewed optics research to have emerged over the past 12 months," with our figure on the front cover and with a link to the interactive applet we made to illustrate the experiment and data.
- Our Optics Letters paper about time gated heralded single photons was discussed in Editor's Choice in Science (327, 251) on 15 January 2010.
talks
- Photon subtraction from travelling fields - recent experimental applications, at the 2nd International Conference on Quantum Information and Technology (ICQIT), Tokyo, Japan, 21 October 2010.
- Continuous variable qubit state engineering, at The 10th International Conference on Quantum Communication, Measurement and Computation (QCMC), Brisbane, Australia, 22 July 2010.
- Optical qubit of continuous-variable states, at XIII International Conference on Quantum Optics and Quantum Information (ICQOQI), Kiev, Ukraine, 31 May 2010.
- Non-Gaussian state generation and manipulation, at International Conference on Quantum Information Processing and Communication (QIPC), Rome, Italy, 21 September 2009.
- Narrow bandwidth optical Schrödinger kitten states and single photons, at The 8th International Conference on Quantum Communication, Measurement and Computing (QCMC), Tsukuba, Japan, 29 November 2006.