Research interests
We study quantum phenomena, quantum information processing, and quantum simulation in nano-scale condensed matter systems and AMO systems with quantum optics theory. Research in this area has been driven both by the urge to understand smaller, better, and more coherent quantum mechanical systems and by the rapid progress in nanotechnology.
On the condensed matter side, our research includes
- superconducting quantum computing
- decoherence and understanding of low-frequency noise
- detector backaction noise
- quantum simulation of many-body physics
On the quantum optics and quantum control side, our research includes
- laser cooling and quantum engineering of nanomechanical systems
- quantum control
- ion trap quantum computing
- atomic Josephson junctions
- Bose-Einstein condensation of exciton-polaritons
Recent Activities
I. Quantum engineering of nanomechanical systems:
cooling, entanglement, equeezing, teleportation, and engineering Schroedinger cat state for nanomechanical systems.
- L. Tian, ``Ground state cooling of nanomechanical resonator via parametric linear
coupling", accepted by Phys. Rev. B, arXiv:0809.4459.
- K. Jacobs, L. Tian, and J. Finns, ``Engineering superposition states and tailored probes for
nano-resonators via open-loop control", Phys. Rev. Lett. 102, 057208 (2009).
- L. Tian, M S Allman, and R. W. Simmonds, ``Parametric coupling between macroscopic quantum resonators",
New J. Phys. 10, 115001 (2008).
- L. Tian & S. M. Carr, ``Quantum teleportation between nanomechanical modes'', Phys, Rev. B 74, 125314
(2006).
- L. Tian, ``Entanglement from a nanomechanical resonator weakly coupled to a single Cooper-pair box'', Phys. Rev. B 72, 195411 (2005).
II. Quantum information processing in nanoscale systems:
scalable quantum protocols for quantum computing, cavity QED approach to probe and manipulate
two-level systems in superconducting systems, continuous measurement of low-frequency noise.
- L. Tian and et al., ``Universal quantum degeneracy point for superconducting qubits", in preparation (2009).
-
L. Tian and K. Jacobs, ``Quantum manipulation of low-frequency fluctuators with superconducting resonator", Phys. Rev. B 79, 144503 (2009).
-
L. Tian and K. Jacobs, ``A Controllable Interaction between Two-Level Systems inside a Josephson Junction", accepted by IEEE Appl. Super. (2009).
- L. Tian & R. W. Simmonds, ``Josephson junction microscope for low-frequency fuctuators'', Phys. Rev. Lett. 99, 137002 (2007).
- L. Tian, ``Correcting low-frequency noise with continuous measurement'', Phys. Rev. Lett. 98, 153602 (2007).
III. Quantum simulation of quantum many body physics:
effect of statistics on correlation functions, nonlinear effects in nanoscale systems, implementing many body Hamiltonian in semiconductor photonic system and other nanoscale devices.
- S. Utsunomiya, L. Tian, G. Roumpos, C. W. Lai, N. Kumada, T. Fujisawa, M. Kuwata-Gonokami, A. Loeffler, S. Hoefling, A. Forchel and Y. Yamamoto, ``Observation of Bogoliubov excitations in excitonpolaritoncondensates'', Nature Physics 4, 700 (2008).
- Y.C. N. Na, S. Utsunomiya, L. Tian, & Y. Yamamoto, ``Strongly Correlated Polaritons in a Two-Dimensional Array of Photonic Crystal Microcavities'', Phys. Rev. A 77, 031803 (2008).
- L. Tian, F. Fujiwara, T. Byrnes, & Y. Yamamoto, ``Interference in the Mott Insulator State of Distinguishable Particles'', submitted, see arXiv/cond-mat/0705.2023 (2007).