Non-Reciprocal interaction in granular fluid

Kiwing To^1*, Chi-Ho Chou¹, Jung-Ren Huang¹

¹Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Kiwing To, email:ericto@gate.sinica.edu.tw

Non-reciprocal interaction [1] violates Newton's Third Law of Motion such that the force F_AB acting on an object (A) by another object (B) does not equal and opposite to the reaction force F_BA on B by A. In this situation, the action-reaction symmetry (ARS) is broken. A non-reciprocity parameter which quantifies the extend of broken ARS can be defined as NRP≡|F_AB+F_BA|. In this talk, we report our experimental measurement of the depletion interaction [2] of two identical objects in a granular fluid which composed of plastic beads vibrated vertically by an electromagnetic shaker. Temperature gradience is imposed on the fluid by different surface coating on the bottom of the shaker as a source of the ARS. We find that NRP in this situation is related to the transfer entropy in in the granular between the two objects, respectively. (Funded by MOST #111-2112-M-001-030.)

References:
[1] A. V. Ivlev, J. Bartnick, M. Heinen, C.-R. Du, V. Nosenko, and H. Löwen, “Statistical mechanics where Newton’s third law is broken,” Phys. Rev. X 5, 011035 (2015); Sarah A.M. Loos and Sabine H. L. Klapp, “Irreversibility, heat and information flows induced by non-reciprocal interactions”, New J. Phys. 22, 123051 (2020).
[2] Melby, P., Prevost, A., Egolf, D. A. & Urbach, J. S. Depletion force in a bidisperse granular layer. Phys. Rev. E 76, 051307 (2007).

Keywords: Non-reciprocal interaction, Granular fluid, Depletion force, Transfer entropy, Brownian motion