- Driven Nonlinear Systems: Quantum fluctuations, Multistability and Switching rate.
- Giant Artificial Atoms: Time-delay and Memory effects in quantum systems, Quantum optics in new regimes.
- New Physics by Floquet Engineering: Topology & Many-body Physics in Phase Space Lattices, Dynamical Crystals
- Superconducting quantum circuits, Circuit QED (Circuit Quantum Electro-Dynamics)
- Hybrid quantum systems, Circuit QAD (Circuit Quantum Acoustic-Dynamics), Quantum (opto-)mechanical systems
- Quantum measurement & feedback control, Quantum computing and Quantum simulation
2015.09-Present: Responsible for a junior research group funded by Carl-Zeiss-Stiftung @ TFP, KIT, Germany
o Topics: Floquet Physics & Engineering, Topology and Quantum Many-body Physics, Quantum Optics with superconducting circuits
o Results: We explore the possible new physics by Floquet engineering. Using ultracold atoms in stroboscopic 1D optical lattice, we propose the concept of Dynamical Crystals and Topology & Many-body Physics in Phase Space Lattices. We also investigate the quantum optics and microwave photonics with superconducting circuits, especially the effects related to the size of artificial atoms: time-delay effects in quantum systems.
2014.09-2015.08: Postdoc @ MC2, Chalmers University of Technology, Sweden
o Topics: Quantum Acoustics with Surface Acoustic Waves
o Results: We work on a hybrid system, which couples the transmon in circuit QED to the propagating mechanical modes of Surface Acoustic Wave (SAW). This is an analogue of circuit QED system but replacing the microwave photons by SAW phonons. We find the transmon decays polynomially rather than exponentially in the phonon bath. We calculate the second order correlation function in the weak driving limit.
o Main Collaborators: Prof. Göran Johansson, Dr. Anton Frisk Kockum, Prof. Per Delsing's experimental group
2010.09-2014.08: 3-year PhD student and 1-year Postdoc @ TFP, Karlsruhe Institute of Technology (KIT), Germany
o Topics: Periodically driven quantum system, Floquet physics
o Results: The first topic we are interested in is the environment's dissipation-induced switching rate, between the multiple meta-stable states in periodically driven system. The switching rate behaves qualitatively differently in the semiclassical regime and quantum regime. Our work identifies there is also a crossover regime and calculates the corresponding quantum critical temperature [PRA 87, 062117(2013)]. The second topic we focus on is the dynamical tunnelling between multiple meta-stable states. Our work connects the periodic structure of periodically driven system in phase space to the solid state physics. We propose the idea of phase space crystals [PRL 111, 205303 (2013)]. This may provide a new way to simulate the condense matter phenomena by synthesizing lattice structures in phase space [New J. Phys. 18 (2016) 023006].
o Main Collaborators: Dr. Michael Marthaler, Dr. Vittorio Peano, Prof. Mark Dykman, Prof. Gerd Schön
2008.06-2010.08: Graduate student @ Department of Physics, Beijing Normal University, China
o Topics: Quantum measurement, Quantum feedback control, Quantum trajectory theory
o Results: In the direction of quantum measurement, we focus on the topic of measuring errors due to the thermal and quantum fluctuations in Josephson Bifurcation Amplifier (JBA). Using the quantum master equation method, we find there is a linear scaling behaviour of measuring error rate near the bistability critical point in the deep quatum regime [EPL, 90 (2010) 10011, PRE 84, 011144 (2011)], diffrent from the 3/2-power law in the semiclassical regime. In the direction of quantum feedback control, we work on the topic of qubit state engineering in circuit QED system. Based on the method of quantum trajectory theory, we propose how to deterministically create and stabilize two-qubit entanglement states in circuit QED by homodyne-mediated feedback control [PRA 82, 032335 (2010)].
o Main Collaborators: Prof. Xinqi Li, Prof. Zhigang Zhen, Prof. Yijin Yan
Grants and Scholarships
Carl-Zeiss-Stiftung Nachwuchsprogramm 2015 zur Förderung von Postdoktorand
Period: Sept. 2015 - Aug. 2017
KHYS Visiting Researcher Scholarship, KIT
Period: 01.04.2014 – 30.09.2014
- Chinese Government Scholarship for Studying Abroad, 09.2010-08.2012
- Individuelle Förderung für Doktoranden aus dem Ausland-DAAD-STIBET, 12.2010-05.2011
09. 2015 — present Postdoc, TFP, Karlsruhe Institute of Technology (KIT), Germany
09. 2014 — 08. 2015 Postdoc, MC2, Chalmers University of Technology, Sweden
07. 2013 — 08. 2014 Postdoc, TFP, Karlsruhe Institute of Technology (KIT), Germany
06. 2010 — 08. 2010 Research Assistant, Department of Chemistry, Hong Kong Uni. of Science and Technology, Hong Kong
07.2013 PhD thesis defended in BNU, Thesis title: Quantum Effects in Driven Nonlinear Systems
09.2010 — 08.2012 Studying in KIT supported by Chinese Government Scholarship
09.2009 — 08.2013 PhD student,
Department of Physics, Beijing Normal University (BNU), Beijing, China
TFP, Karlsruhe Institute of Technology (KIT), Germany
09.2006 — 07.2009 Master student, Department of Physics, Beijing Normal University (BNU), Beijing, China
09.2001 — 07.2005 Undergraduate Student, Department of Physics, Beijing Normal University (BNU), Beijing, China