Tim Halpin-Healy 
Professor of Physics, Barnard College, Columbia University  
Telephone: (212)854-5102 
Ph.D. 1987
Harvard University  
Mentors: Bert Halperin,
Mehran Kardar, Edouard Brézin

A.B. 1981 
Princeton University  
Thesis Advisor: David Gross
1+1 KPZ Class PDFs: Ulam, Tracy-Widom & Baik-Rains, THH/LL, Phys. Rev. E 89, 010103 (2014). *Editor's Suggestion 

2+1 KPZ: Experiment,
Europhys. Lett. 105, 50001 (2014).
*Editor's Choice 

2+1 KPZ: Universal Distributions, THH,
Phys. Rev. Lett. 109, 170602 (2012).

Phys. Rev. E88, 042118 (2013). 

The Dynamics of Conformity & Dissent,
Arne Soulier & THH, Phys. Rev. Lett. 90, 258103 (2003).

Directed Polymers vs. Directed Percolation PRE58, R4096 (1998). 

Chemical Wave Refraction Phenomena, Sin-Chun Hwang BC'96, & THH, Phys. Rev. E54, 3009 (1996).

Kinetic Roughening, Stochastic Growth, Directed Polymers & all that,THH & Y-C Zhang, Phys. Rep. 254, 215-415 (1995).  
Disturbing the Random Energy Landscape,  THH & D. Herbert BC'92, Phys. Rev. E48, 1617RC (1993). 
Depinning by Quenched Randomness, Phys. Rev. Lett. 67, 3463C (1991). 
Diverse Manifolds in Random Media, THH, Phys. Rev. Lett. 62, 442 (1989).  
My primary interests include phase transitions, critical phenomena, & the renormalization group; secondary concerns: kinetic roughening, reaction-diffusion systems, nonlinear dynamics, Nature's pattern formation. In recent years, I have concentrated my efforts on understanding the statistical mechanics of directed polymers in random media (DPRM), a baby version of the spin-glass and one of the few tractable problems in ill-condensed matter. Because of a mapping via the stochastic Burgers equation, the DPRM pays off handsomely, with important implications for vortex-line wandering in disordered superconductors, the propagation of flame fronts, domain-wall roughening in impurity-stricken magnets, as well as the dynamic scaling properties of Eden clusters. Tools of the trade are tied to the renormalization group in modern form, including both numerical and analytical approaches. Listed at left are a number of papers that I take particular pride in. They give a good sense of the statistical mechanical problems I like to work on.
Columbia Graduate Students:
Martin Z CU*91,  Yi-Kuo Yu CU*94,  N.-N. Pang CU*95,  Arne Soulier CU*02,  Aylin Cimenser CU*04 

Barnard Researchers, selection:
B. Tamminga BC'93,  Yick Chan BC'93,  Sheila David BC'95,  Hasmik Diratzouian BC'96,  Rocio Patino BC'96,  Michelle Baird BC'96,  Rocky Novoseller BC'98, 
Mary Pratt BC'01,  Natalie Arkus BC'03,  WKWong BC'06,  Whitney Becker BC'07,  Erin Sperry BC'11,  Yuexia Lin BC'15. 

CU Summer HS Program:
i) Session I: Expt'l & Theoretical Physics-
Class: '5, '6, '7, '8, '9, '10, '11, '12, '13, '14   ii) Session II: BootCamp for Budding String Theorists- Inaugural Class-2009, '10, '11

Director, emeritus, Barnard College Centennial Scholars Program 
Director, BC Science & Public Policy Program; co-teach Science & The State

NSF Grant 
South Africa Trip 
KPZ Review w/Zhang 
Recent Talk: "The Dynamics of Conformity & Dissent"  
Another: "25 Years of KPZ"  
Senior Thesis (1981)- Are Glueballs Found? Answer: Maybe (1995), though they're a slippery lot... (2005) ;-> 
Troisième Cycle Lectures (EPFL- Lausanne, Switzerland)- I. Interfacial Critical Phenomena, II. 3d Critical Wetting, III. Diverse Manifolds, IV. Realm of KPZ 

Here, some optimized geometry: DPRM River Basin Delta

This relates to my work on the statistical mechanics of extremal trajectories in a random energy landscape. The immediate goal is to explain how the geometric complexity of optimal patterns differs from those generated by random processes. We'd like to understand to what degree various directed patterns found in Nature, whether they be geomorphological (e.g., the Nile Delta) or biological (e.g., capillary blood vessel networks in the human eye) in character, represent globally optimal solutions within their given context. Plenty of info to be found in section 5.8 of the KPZ review paper that I wrote with Y.-C. Zhang @Universite Fribourg, Switzerland. See also paper above coauthored by Devorah Herbert, shown here on graduation day with Bonnie Tamminga, another Barnard physics major who spent a summer working on KPZ statistical mechanics. Devorah is a playwright; Bonnie went on for a PhD in experimental particle physics, a distinguished Leon Ledermann Post-Doctoral Fellowship at FermiLab, and is now Horace D Taft Professor of Physics at Yale University, studying neutrinos.

Finally, an abstract regarding a separate DPRM issue: Tuning the Trip to KPZ Asymptopia