The Quantum Technologies Group is exploring the bizarre world of quantum mechanics. Its properties, such as superposition, coherence, entanglement, teleportation, etc., have given rise to various paradoxes (Schrodinger's cat, the Einstein-Podolsky-Rosen paradox, etc.). Back in the early '80s, Feynman was among the first to suggest that these principles may enable us to process information at much faster speeds than any classical computer. Ever since, people have been trying to harness the power of quantum mechanics and build a quantum computer. This subject is still in its infancy, but already industry giants, such as Microsoft, IBM and Google, are trying to make use of a quantum computer. Another promising application of quantum mechanics is in cryptography. It provides unprecedented means of transmitting encrypted information over a public channel. Quantum information and quantum computation are rapidly developing arenas of basic as well as applied research. The group performs research at both UT and ORNL.

For more information, e-mail: quantum@tennessee.edu

Dr. Pooser is an expert in continuous variable quantum optics. He has developed a program based on quantum sensing over a number of years at ORNL, followed by
fledgling efforts in quantum computing. He has been working to demonstrate that continuous variable quantum optics, quantum noise reduction in particular, has important
uses in the quantum information field. He is also interested in highlight the practicality of these systems,
demonstrating their ease of use and broad applicability. Dr. Pooser heads up work in both
experimental and theoretical quantum computing research. His goal is to show that quantum control and
error correction required in sensing applications are directly applicable to quantum computing efforts. The
deterministic nature of these systems is a strong draw and motivation that will eventually lead to practical
applications. He has followed this model of quantum sensors as a showcase for the technologies that will
enable quantum computing to good results.

Dr. Qi is a leading expert in experimental quantum communications. He is well known for his work in both discrete-variable and continuous-variable Quantum Key Distribution (QKD), including the first demonstration of decoy-state QKD, the discovery and implementation of the first successful attack (time-shift attack) against commercial QKD, the proposal of one of the first attacks on free-space QKD (the spatial-mode attack), the proposal of QKD protocols based on time and frequency coding, and the invention and demonstration of measurement-device-independent QKD. He has extensive experimental experience in discrete-variable QKD, continuous-variable QKD and quantum hacking.

Dr. Siopsis is a theoretical high energy
physicist with over 100 publications. In recent years, his research has focused on quantum gravity and
related issues (holography, entanglement, the information loss paradox), and applications to condensed
matter physics. He has trained several PhD students who have embarked on promising careers, and introduced
undergraduates as well as high school students to research in quantum physics and fundamental
interactions. Recently, he has started working on quantum computing and quantum information processing
in collaboration with members of the
Quantum Information Science group at ORNL. He has also developed and taught a graduate level
course on Quantum Computation and Quantum Information.

- On the Physical Review B Kaleidoscope.
- 'Quantum mechanical squeezing' enables quantum state atomic force microscopy.
- Physicists extend quantum machine learning to infinite dimensions.
- Physicists Developing Solutions to Keep Digital Information Safe at Sea.
- On the Physical Review A Kaleidoscope.
- Nano-trapped molecules are potential path to quantum devices.

- K. Yeter and G. Siopsis,
*Quantum Computation of Scattering Amplitudes in Scalar Quantum Electrodynamics,*arXiv:1709.02355 [quant-ph] (2017). - S. Das, S. Khatri, G. Siopsis, and M. M. Wilde,
*Fundamental limits on quantum dynamics based on entropy change,*arXiv:1707.06584 [quant-ph] (2017). - S. Das, G. Siopsis, and C. Weedbrook,
*Continuous-variable quantum Gaussian process regression and quantum singular value decomposition of non-sparse low rank matrices,*arXiv:1707.00360 [quant-ph] (2017). - K. Bradler, G. Siopsis, and A. Wozniakowski,
*Covert Quantum Internet,*arXiv:1704.07281 [quant-ph] (2017). - K. V. Garapati, M. Salhi, S. Kouchekian, G. Siopsis, and A. Passian,
*Poloidal and toroidal plasmons and fields of multilayer nanorings*, Phys. Rev. B**95**, 165422 [arXiv:1704.01010 [physics.optics]] (2017). - A. Passian and G. Siopsis,
*Quantum state atomic force microscopy,*Phys. Rev. A**95**, 043812 [arXiv:1703.08077 [quant-ph]] (2017). - R. Balu, D. Castillo, G. Siopsis, and C. Weedbrook,
*Continuous-time limit of topological quantum walks,*Proceedings Volume 10193, Ultrafast Bandgap Photonics II; 1019319 [arXiv:1611.07457 [quant-ph]] (2017). - C. C. W. Lim, F. Xu, G. Siopsis, E. A. Chitambar, P. G. Evans, and B. Qi,
*Loss-tolerant quantum secure positioning with weak laser sources*, Phys. Rev. A**94**, 032315 [arXiv:1607.08193 [quant-ph]] (2016). - K. Bradler, T. Kalajdzievski, G. Siopsis, and C. Weedbrook,
*Absolutely covert quantum communication,*arXiv:1607.05916 [quant-ph] (2016). - E. Diamanti, H.-K. Lo, B. Qi, and Z. Yuan,
*Practical challenges in quantum key distribution,*npj Quantum Information 2, 16025 [arXiv:1606.05853 [quant-ph]] (2016). - H.-K. Lau, R. Pooser, G. Siopsis, and C. Weedbrook,
*Quantum machine learning over infinite dimensions,*Phys. Rev. Lett.**118**, 080501 [arXiv:1603.06222 [quant-ph]] (2017). - B. Qi, H.-K. Lo, C. C. W. Lim, G. Siopsis, E. A. Chitambar, R. Pooser, P. G. Evans, and W. Grice,
*Free-space reconfigurable quantum key distribution network*, IEEE ISCOS Conference, [arXiv:1510.04891 [quant-ph]] (2015). - A. Passian and G. Siopsis,
*Strong quantum squeezing near the pull-in instability of a nonlinear beam,*Phys. Rev. A**94**, 023812 (2016). - M. Salhi, A. Passian, and G. Siopsis,
*Toroidal nano-traps for cold polar molecules,*Phys. Rev. A**92**, 033416 [arXiv:1508.06534 [cond-mat.mes-hall]]. - K. Marshall, R. Pooser, G. Siopsis, and C. Weedbrook,
*Quantum simulation of quantum field theory using continuous variables,*Phys. Rev. A 92, 063825; arXiv:1503.08121 [quant-ph] (2015). - B. Qi, P. Lougovski, R. Pooser, W. Grice, and M. Bobrek,
*Generating the local oscillator "locally" in continuous-variable quantum key distribution based on coherent detection,*Phys. Rev. X**5**, 041009; arXiv:1503.00662 [quant-ph] (2015). - B. Qi and G. Siopsis,
*Loss-tolerant position-based quantum cryptography,*Phys. Rev. A**91**, 042337 (2015) [arXiv:1502.02020 [quant-ph]]. - K. Marshall, R. Pooser, G. Siopsis, and C. Weedbrook,
*Repeat-until-success cubic phase gate for universal continuous-variable quantum computation,*Phys. Rev. A**91**, 032321 (2015) [arXiv:1412.0336 [quant-ph]].

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