Post-Doc at ICTP, Italy. Apr 1998–Oct 1999.

Post-Doc at The University of Goettingen, Germany. Oct 1999–Sep 2000.

National University of Singapore. 2 weeks in March 2001.

ICTP, Italy. 20 Sep 2002–20 Oct 2002.

Universitaet Essen, Germany.  20 Oct 2002–17 Dec 2002.

Chinese University of Hong Kong. 3 Nov 2003–2 Feb 2004.

The University of Hong Kong. 13 Jun 2004–12 Aug 2004.

University Bayreuth, Germany. 1 Jun 2005–31 Jul 2005.

Sogang University, South Korea. 21 Dec 2005–31 Dec 2005.

National University of Singapore. One month in Jan–Feb 2006.

Mainz University, Germany.  1 Jun 2006–31 Aug 2006.

Stanford University, USA.  20 Jan 2007–5 Mar 2007.

Taiwan University. 27 Mar 2007–15 Apr 2007.

The University of Tokyo, Japan. 2 Dec 2007–16 Dec 2007.

The University of Warwick, UK. 16 Jan 2008–31 Jan 2008.

The University of Warwick, UK. 10 Jun 2010–24 Jun 2010.

The University of Missouri, USA. 2 Aug 2010–2 Sep 2010.

KIAS, South Korea. 22 May 2011–28 May 2011.

MPIM in Bonn, Germany. 1 Oct 2011–31 Jan 2012.

The University of Bayreuth, Germany.  1 Feb 2012–29 Feb 2012.

Taiwan University. 23 Jan 2014–15 Feb 2014.

KAIST, South Korea. 28 Sep, 2014–11 Oct 2014.

Hong Kong University of Science and Technology, Hong Kong. 9 Feb 2015–15 Feb 2015.

National University of Singapore, Singapore. Jan 6th, 2017–Feb 4th, 2017.

Nagoya University, Japan. Nov 5th, 2017–Nov 17th, 2017.

Korea Institute for Advanced Study (KIAS), Seoul, Korea. Jan 20, 2019–Feb 2, 2019.

National University of Singapore, Singapore. Aug 20, 2023--Aug 28, 2023.

Simons Foundation in New York City & Princeton University & Boston College, USA, Oct 24, 2023--Nov 8, 2023.