From nsantic at ifs.hr Mon Jul 3 13:58:30 2023 From: nsantic at ifs.hr (Neven =?utf-8?B?xaBhbnRpxIc=?=) Date: Mon, 3 Jul 2023 13:58:30 +0200 (CEST) Subject: [seminar] =?utf-8?q?=40IoP=3A_Andr=C3=A1s_Vukics_-_Friday_7th_Ju?= =?utf-8?q?ne_2023_at_13=3A00=2C_1st_wing_lecture_hall?= Message-ID: <1322347806.299049.1688385510153.JavaMail.zimbra@ifs.hr> Seminar @Institute of Physics, Friday 7th June 2023 at 13:00, 1st wing lecture hall Photon-blockade breakdown as a first-order dissipative phase transition in zero dimension Dr. Andr?s Vukics Wigner Research Centre for Physics, Budapest, Hungary I present the relatively recent concept of first-order dissipative phase transitions that can occur in meso- and even microscopic quantum systems. One of the first examples of this phenomenology was the photon-blockade breakdown (PBB) effect, that occurs most simply in a coupled system of a bosonic mode and a qubit. For PBB, an abstract thermodynamic limit has been identified [1], where the coupling between the subsystems goes to infinity without affecting the system size, and this limit was studied in a finite-size scaling approach [2], with scaling exponents determined numerically. Upon discussing the microscopic mechanism and the fully quantum solution, I will assess the neo- and semiclassical models, and the connection with optical bistability. I describe the experimental studies: PBB was first observed in a circuit QED system [3], and the thermodynamic limit could also be modeled on this platform with a bespoke device [4]. The numerical modelling [5] of this latter set of experiments highlighted the role of the higher lying transmon levels and the phase noise. As an outlook, I describe a related phenomenology dubbed transmission-blockade breakdown, that was observed in the rubidium cold-atom ? cavity QED lab of the Wigner Research Centre for Physics [6]. [1] H. J. Carmichael, Phys. Rev. X 5, 031028 (2015). [2] A. Vukics, A. Dombi, J. M. Fink, P. Domokos, Quantum 3, 150 (2019). [3] J. M. Fink, A. Dombi, A. Vukics, A. Wallraff, and P. Domokos, Phys. Rev. X 7, 011012 (2017). [4] R. Sett, F. Hassani, D. Phan, Sh. Barzanjeh, A. Vukics, and J. M. Fink, arXiv:2210.14182 (2022). [5] https://github.com/vukics/cppqed [6] B. G?bor, D. Nagy, A. Dombi, T. W. Clark, F. I. B. Williams, K. V. Adwaith, A. Vukics, P. Domokos, Phys. Rev. A 107, 023713 (2023) Seminar hosts : [ mailto:nsantic at ifs.hr | Neven ?anti? ] i [ mailto:ddominko at ifs.hr | Damir Dominko ] -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image001.png Type: image/png Size: 19855 bytes Desc: not available URL: From ddominko at ifs.hr Mon Jul 3 14:21:03 2023 From: ddominko at ifs.hr (Damir Dominko) Date: Mon, 3 Jul 2023 14:21:03 +0200 Subject: [seminar] Nastupno predavanje dr. sc. Vito Despoja u PETAK 07.07.2023. u 11:00h In-Reply-To: <1132107818.1036560.1688380757375.JavaMail.zimbra@ifs.hr> References: <1132107818.1036560.1688380757375.JavaMail.zimbra@ifs.hr> Message-ID: <68baab2d-0cd0-89e0-f238-0791b6928940@ifs.hr> **petak, 7. srpnja 2023., u 11:00 sati** *Exciton-polaritons in layered van der Waals heterostructures*** **Dr. sc. ***Vito Despoja* *Institute of Physics*** In the first part of the presentation, I will reflect on the latest achievements regarding the development of the theoretical formalism that describes the interaction of photons and electronic excitations in layered van der Waals crystals [1].? In the following I will talk about the results of that formalism which relate to; 1. the excitons intensity vs doping in black phosphorus [1]; 2. the interaction between cavity photons and excitons in transition-metal dichalcogenides (TMDs) and in fullerene (C_60 ) thin films [2,3] and; 3. the interaction between? 'free'? s(TE) photons and excitons (formation of trapped photons) in? WS_2 /hBN and in C_60 multilayers [4,5]. Finally, I will show the advantages and disadvantages of the current research and in which direction the research will continue. The spectral intensity of the s(TE) cavity photon n=1 in the (a) empty Al/Al_2 O_3 /vacuum/Al cavity (N = 0)? and in the cavity supporting C_60 film of thicknesses (b) N = 5,? and (c) N = 25 molecular layers. Here, ?_ex1 , ?_ex2 ? and ?_ex3 denote three of the most intensive ?-excitons in C_60 . [1] D. Novko, K. Lyon, D. J. Mowbray, and V. Despoja Phys. Rev. B 104, 115421 (2021) [2] D. Novko and V. Despoja, Phys. Rev. Research 3, L032056 (2021) [3] V. Despoja and D. Novko, Phys. Rev. B 106, 205401 (2022) [4] V. Despoja and L. Maru?i?, Int. J. Mol. Sci. 23, 6943? (2022) [5] N. Goleni? and V. Despoja, Phys. Rev. B Lett., under review Nastupno?predavanje ?e se odr?ati u predavaonici u 1. krilu Instituta. Predavanje ?ete mo?i pratiti i putem Zoom-a: https://us06web.zoom.us/j/84831165364?pwd=THRSK1VmZDNjS3NBOGplODREYlFTUT09 Meeting ID: 848 3116 5364 Passcode: 098884 Predsjednik Znanstvenog vije?a Instituta za fiziku dr. sc. Damir Stare?ini? _______________________________________________ https://www.phy.pmf.unizg.hr/cgi-bin/mailman/listinfo/seminar -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image.png Type: image/png Size: 209843 bytes Desc: not available URL: