Xinsheng Sean Ling Professor of Physics

Professor Ling joined the faculty of Brown University in 1996. A 1984 graduate of Wuhan University, China, he received his M.S. from the Chinese Academy of Sciences in 1987 and his Ph.D. from the University of Connecticut in 1992. He has done postdoctoral research at Yale University (1992-1994) and the NEC Research Institute at Princeton (1994-1996). Most recently he was a visiting professor at Delft University of Technology in the Netherlands from 2002-2003 and a guest professor at Wuhan University from 2002-2005, a Qianren Plan (千人计划) Visiting Professor at Southeast University (Nanjing) from 2015-2018. Professor Ling received a Research Innovation Award from the Research Corporation in 1998, and he was an A.P. Sloan Fellow from 1998-2001 and a J.S. Guggenheim Fellow from 2002-2003. He was elected a Fellow of the American Physical Society in 2005.

Brown Affiliations

Research Areas

scholarly work

Daniel Y. Ling and Xinsheng Sean Ling, "On the distribution of DNA translocation times in solid-state nanopores: an analysis using Schrödinger's first-passage-time theory", J. Phys.: Cond. Matt. 25, 375102 (2013).

Xinsheng Sean Ling, "METHODS OF SEQUENCING NUCLEIC ACIDS USING NANOPORES AND ACTIVE KINETIC PROOFREADING", World Intellectual Property Organization, WO2013/119784 A1 (

Xinsheng Sean Ling, "Solid-State Nanopores: Methods of Fabrication and Integration, and Feasibility Issues in DNA Sequencing", p.177 in S.M. Iqbal and R. Bashir (eds.), Nanopores: Sensing and Fundamental Biological Interactions, DOI 10.1007/978-1-4419-8252-0_8, Springer Science+Business Media, LLC 2011

Venkat S.K. Balagurusamy, Paul Weinger, & Xinsheng Sean Ling, "Detection of DNA hybridizations using solid-state nanopores", Nanotechnology 21, 335102 (2010).

Hongbo Peng and X.S. Ling, "Reverse DNA translocation through a solid-state nanopore by magnetic tweezers", Nanotechnology, 20, 185101(2009).

Alexandros Pertsinidis and X.S. Ling, "Statics and Dynamics of 2D Colloidal Crystals in a Random Pinning Potential", Physical Review Letters, 100, 028303 (2008).

Sang R. Park, H. Peng, and X.S. Ling, "Fabrication of Nanopores in Silicon Chips Using Feedback Chemical Etching", SMALL 3, 116 (2007).

Shanshan Wu, Sang R. Park, and X.S. Ling, "Lithography-Free Formation of Nanopores in Plastic Membranes using Laser Heating", Nano Letters 6, 2571(2006).

A.J. Storm, J.H. Chen, X.S. Ling, H. Zandbergen, and C. Dekker, "Electron-Beam-Induced Deformations of SiO2 Nanostructures", Journal of Applied Physics 98, 014307 (2005).

Arnold J. Storm, Jiang Hua Chen, X.S. Ling, H. Zandbergen, and C. Dekker, "Fabrication of Solid-State Nanopores with Single Nanometer Precision", Nature Materials, 2, 537 (2003).

A. Pertsinidis and X.S. Ling, "Equilibrium Configurations and Energetics of Point Defects in Two-Dimensional Colloidal Crystals", Physical Review Letters, 87, 098303 (2001).

X.S. Ling, S.R. Park, B.A. McClain, S.M. Choi, D.C. Dender, and J.W. Lynn, "Superheating and Supercooling of Vortex Matter in a Nb Single Crystal: Direct Evidence for a Phase Transition at the Peak Effect from Neutron Diffraction", Physical Review Letters, 86, 712 (2001).

A. Pertsinidis and X.S. Ling, "Diffusion of Point Defects in Two-Dimensional Colloidal Crystals", Nature, 413, 147 (2001).

J. Shi, X. S. Ling, R. Liang, D.A. Bonn, W.N. Hardy, "Giant Peak Effect Observed in an Ultra-pure YBa2Cu3O7 Crystal", Physical Review, B Rapid Communications, 60, R12593 (1999).

X.S. Ling, J.E. Berger, and D. E. Prober, "Nature of Vortex Lattice Disordering at the Onset of the Peak Effect", Physical Review, B Rapid Communications, 57, R3249 (1998).

X.S. Ling, J.I. Budnick, and B.W. Veal, "Peak Effect and Its Disappearance in Superconducting YBCO Crystals", Physica C, 282, 2191 (1997).

X.S. Ling, H.J. Lezec, M.J. Higgins, J.S. Tsai, J. Fujita, Y. Nakamura, Chao Tang, P.M. Chaikin, and S. Bhattacharya, "Nature of Phase Transitions of Superconducting Wire Networks in a Magnetic Field", Physical Review Letters, 76, 2989 (1996).

C. Tang, X.S. Ling, S. Bhattacharya, and P.M. Chaikin, "Peak Effect in Superconductors: Melting of Larkin Domains", Europhysics Letters, 35, 597 (1996).

X.S. Ling, J.D. McCambridge, N.D. Rizzo, J.W. Sleight, D.E. Prober, L.R. Motowidlo, and B.A. Zeitlin, "Fluctuation Effects on a Strongly Pinned Vortex Lattice in a Thin Type-II Superconducting Wire", Physical Review Letters, 74, 805 (1995).

S. Field, J. Witt, F. Nori, and X.S. Ling, "Superconducting Vortex Avalanches", Physical Review Letters, 74, 1206 (1995).

X. S. Ling, "Flux dynamics in high-temperature superconductors", (Ph.D. thesis, University of Connecticut, May 1992), reprints available from UMI Microfilm.

X.S. Ling and J.I. Budnick, "AC Magnetic Susceptibility Studies of Type-II Superconductors: Vortex Dynamics", in Magnetic Susceptibility of Superconductors and Other Spin Systems, Edited by R.A. Hein, T.L. Francavilla, & D.H. Liebenberg, (Plenum, New York, 1991), p.377.

research overview

Experimental Condensed Matter Physics and Nanobioscience:

Current Research: Molecular Biophysics, nanopore DNA sequencing

research statement

I'm fascinated by DNA and RNA polymerases' amazing ability in discriminating between bases with astonishing accuracy.  This "proofreading" ability of biological micromachines is well beyond what was allowed by equilibrium thermodynamics of the specific Watson-Crick pairing energies, as first pointed out by physicist John Hopfield in the 1970s.  Hopfield, and later Ninio, suggested the concept of "kinetic proofreading".  My current interest is to build solid-state devices capable of kinetic proofreading functions.

funded research

NSF-DMR:Condensed Matter Physics"Statics and Dynamics of 1D and 2D Colloidal Lattices with Random Pinning" (July 15, 2010-July 14, 2013), $360,000.

NIH National Human Genome Research Institute: R21 "Hybridization-Assisted Nanopore DNA Sequencing" (Aug.1, 2007-July 31, 2011), $820,000.

DOE Basic Energy Sciences:"Neutron scattering studies of vortex matter" (Aug.15, 2007-July 31, 2011), $600,685.

National Science Foundation Grant, "NIRT: DNA Sequencing and Translocation Studies using Electrically-Addressable Nanopore Arrays", (07/04-06/08) $1,550,000 (Brown $900,000, Harvard $650,000) (PI: Ling (Brown), Co-PIs: A. Meller (Harvard), D.R. Nelson (Harvard), and J. Oliver (Brown)).

National Science Foundation Grant, DMR: "Investigation of Vortex Matter Phase Transitions in Type-II Superconductors using Small Angle Neutron Scattering and Complementary Techniques", (07/04-06/07), $330,000.

National Science Foundation Grant, "NER: DNA Sequence Detection using Novel Solid-State and Soft Nanopores", (09/03-08/04), $100,000.

National Science Foundation Grant, MRI: "Acquisition of a Scanning Probe Microscope for Studies of Biomolecules and Nanoscale Materials and Devices", (07/03-06/04), $133,000 (PI: J. Tang, co-PIs: Ling, Valles and Xiao).

Salomon Faculty Research Award for research in nanopore biophysics (02-03).

National Science Foundation Grant, MRI: "Acquisition of a Workhorse Electron Beam Lithography System for Microstructured Materials and Devices Research", (07/01-06/02), $151,200.

National Science Foundation Grant, DMR: "Novel Studies of Vortex Matter and Peak Effect using In-Situ Neutron Scattering and AC Magnetization", (07/01-06/04), $277,000.

National Science Foundation Grant, SGER: "In-Situ Measurements of Small Angle Neutron Scattering and AC Magnetic Susceptibility of Vortex Matter", (07/00-06/01), $59,949.

Salomon Faculty Research Award for research in vortex matter (00-01).

National Science Foundation Grant, DMR: "Novel Studies of Two-Dimensional Colloidal Crystals in Pinning Potentials", (07/98-06/02), $240,000.

Petroleum Research Fund Grant, "Novel Studies of Two-Dimensional Colloidal Crystals in Pinning Potentials", (07/98-06/99), $35,000.

Salomon Faculty Research Award for research in 2D colloidal crystals (98-99).

Research Corporation, "Experimental Studies of Topological Defects and Order in 2D Colloidal Crystals", (07/98-06/00), $35,000.

Alfred P. Sloan Fellowship, (1998) $35,000.