{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T16:09:09Z","timestamp":1788970149797,"version":"build-2803163510"},"reference-count":51,"publisher":"AIP Publishing","issue":"10","funder":[{"DOI":"10.13039\/501100001502","name":"Department of Atomic Energy, Government of India","doi-asserted-by":"crossref","award":["1603\/2\/2020\/IoP\/R&D-II\/15028"],"award-info":[{"award-number":["1603\/2\/2020\/IoP\/R&D-II\/15028"]}],"id":[{"id":"10.13039\/501100001502","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,9,14]]},"abstract":"<jats:p>We introduce a Langevin formulation of Vicsek-like active particles, in which orientations evolve through finite-rate relaxation toward the local mean direction, with alignment strength J and rotational diffusivity Dr, thereby combining Vicsek-type local consensus with XY-like orientational dynamics. Using large-scale numerical simulations, we determine the nonequilibrium phase diagram as a function of activity and alignment rate. For example, at intermediate activity and in sufficiently large systems, increasing the alignment rate drives a sequence of transitions from a homogeneous isotropic state to polar bands, a cross-sea phase of intersecting bands, a homogeneous polar state, and ultimately a micro-clustered regime. The isotropic-to-polar transition is strongly first-order, as evidenced by Binder cumulants and bimodal distributions of local polarization and density, indicating coexistence of gas-like and liquid-like regions. Near the onset of collective motion, the band size increases with activity but depends non-monotonically on the alignment rate. Further increasing the alignment rate drives the system through the cross-sea and homogeneous polar phases before enhanced density fluctuations lead to micro-clustering. Our results demonstrate that finite-time orientational relaxation acts as a control parameter that qualitatively restructures collective behavior in polar active matter.<\/jats:p>","DOI":"10.1063\/5.0348008","type":"journal-article","created":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T15:21:19Z","timestamp":1788967279000},"update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Finite-time orientational relaxation restructures collective motion in polar active matter"],"prefix":"10.1063","volume":"165","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6681-3181","authenticated-orcid":false,"given":"Rajneesh","family":"Kumar","sequence":"first","affiliation":[{"name":"Institute of Physics, Sachivalaya Marg, Sainik School 1 , Bhubaneswar 751005,","place":["India"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-0068-9015","authenticated-orcid":false,"given":"Subhransu Sekhar","family":"Mishra","sequence":"additional","affiliation":[{"name":"Institute of Physics, Sachivalaya Marg, Sainik School 1 , Bhubaneswar 751005,","place":["India"]},{"name":"Homi Bhabha National Institute (HBNI), Training School Complex 2 , Anushakti Nagar, Mumbai 400094,","place":["India"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1759-125X","authenticated-orcid":false,"given":"Debasish","family":"Chaudhuri","sequence":"additional","affiliation":[{"name":"Institute of Physics, Sachivalaya Marg, Sainik School 1 , Bhubaneswar 751005,","place":["India"]},{"name":"Homi Bhabha National Institute (HBNI), Training School Complex 2 , Anushakti Nagar, Mumbai 400094,","place":["India"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"317","published-online":{"date-parts":[[2026,9,9]]},"reference":[{"key":"2026090906464549500_c1","doi-asserted-by":"publisher","first-page":"1143","DOI":"10.1103\/revmodphys.85.1143","article-title":"Hydrodynamics of soft active matter","volume":"85","year":"2013","journal-title":"Rev. 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