BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Kinetic Theory of Fermi-Boson Systems DTSTART:20260701T140000Z DTEND:20260701T160000Z DTSTAMP:20260906T140716Z UID:a2408514-a1c0-44a6-8f90-6f3676852397 SEQUENCE:1 CREATED:20260626T083146Z DESCRIPTION: The collective dynamics of strongly interacting quantum matte r\, where fermionic carriers and bosonic excitations coexist and mutually influence one another\, represent a challenging and rapidly growing active field in theoretical physics. While the hydrodynamic and Vlasov limits ar e well established for Fermi-Dirac systems\, a fully self-consistent treat ment that places species of differing natures on equal footing remains lar gely unexplored. This work addresses that gap by going beyond the mean-fie ld truncation of the BBGKY hierarchy\, explicitly quantizing the collectiv e charge oscillations and promoting the resulting plasmons to a dynamical bosonic species governed by their own kinetic equation\, coupled to the fe rmionic sector through effective inter-species force terms. The framework is applied to two-dimensional Dirac materials\, specifically monolayer gra phene\, whose linear band structure and gapless plasmonic spectrum make it a natural platform for this study. The thermodynamic quantities of both s ectors are derived to construct the fermion-boson coupling via ponderomoti ve and refractive forces\, and from the resulting multispecies secular det erminant\, the collective mode spectrum is extracted via energy-loss funct ion. A modified plasmon mode is found\, shifted in frequency and intrinsic ally damped through the complex bosonic polarizability\, with a charge-osc illation character confirmed by mode decomposition. A second spectral feat ure is analytically identified as an anti-resonance and a closed-form disp ersion relation is derived for it. Finally\, kinetic simulations uncover a sound-like instability with non-zero real frequency and positive growth r ate\, absent in the bare fermionic system. Theory and simulation agree acr oss a range of parameters\, for which it was determined that the sound mod e develops curvature at large μ/kBT >\;>\; 1. LAST-MODIFIED:20260626T083146Z LOCATION:Online URL:http://df.vps.tecnico.ulisboa.pt/en/events/kinetic-theory-of-fermi-bos on-systems/ X-ALT-DESC;FMTTYPE=text/html:

The collective dyn amics of strongly interacting quantum matter\, where fermionic carriers an d bosonic excitations coexist and mutually influence one another\, represe nt a challenging and rapidly growing active field in theoretical physics. While the hydrodynamic and Vlasov limits are well established for Fermi-Di rac systems\, a fully self-consistent treatment that places species of dif fering natures on equal footing remains largely unexplored. This work addr esses that gap by going beyond the mean-field truncation of the BBGKY hier archy\, explicitly quantizing the collective charge oscillations and promo ting the resulting plasmons to a dynamical bosonic species governed by the ir own kinetic equation\, coupled to the fermionic sector through effectiv e inter-species force terms.

The framework is applied to two-dim ensional Dirac materials\, specifically monolayer graphene\, whose linear band structure and gapless plasmonic spectrum make it a natural platform f or this study. The thermodynamic quantities of both sectors are derived to construct the fermion-boson coupling via ponderomotive and refractive for ces\, and from the resulting multispecies secular determinant\, the collec tive mode spectrum is extracted via energy-loss function.

A modi fied plasmon mode is found\, shifted in frequency and intrinsically damped through the complex bosonic polarizability\, with a charge-oscillation ch aracter confirmed by mode decomposition. A second spectral feature is anal ytically identified as an anti-resonance and a closed-form dispersion rela tion is derived for it. Finally\, kinetic simulations uncover a sound-like instability with non-zero real frequency and positive growth rate\, absen t in the bare fermionic system. Theory and simulation agree across a range of parameters\, for which it was determined that the sound mode develops curvature at large μ/kBT >\;>\; 1.

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