Unusual ergodic and chaotic properties of trapped hard rods

Debarshee Bagchi, Jitendra Kethepalli, Vir B. Bulchandani, Abhishek Dhar, David A. Huse, Manas Kulkarni, Anupam Kundu

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We investigate ergodicity, chaos, and thermalization for a one-dimensional classical gas of hard rods confined to an external quadratic or quartic trap, which breaks microscopic integrability. To quantify the strength of chaos in this system, we compute its maximal Lyapunov exponent numerically. The approach to thermal equilibrium is studied by considering the time evolution of particle position and velocity distributions and comparing the late-time profiles with the Gibbs state. Remarkably, we find that quadratically trapped hard rods are highly nonergodic and do not resemble a Gibbs state even at extremely long times, despite compelling evidence of chaos for four or more rods. On the other hand, our numerical results reveal that hard rods in a quartic trap exhibit both chaos and thermalization, and equilibrate to a Gibbs state as expected for a nonintegrable many-body system.

Original languageEnglish (US)
Article number064130
JournalPhysical Review E
Issue number6
StatePublished - Dec 2023

All Science Journal Classification (ASJC) codes

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics


Dive into the research topics of 'Unusual ergodic and chaotic properties of trapped hard rods'. Together they form a unique fingerprint.

Cite this