07:59:18 From Leon Balents to All panelists : good morning ! 07:59:28 From Eun-Ah Kim - Coordinator to All panelists : morning 08:05:55 From Yuxuan Wang to All panelists : Can hands be raised during the talk or should we wait until the end to raise hands? 08:07:07 From Eun-Ah Kim - Coordinator : You may raise hands during the talk. Just know that we will only get to it at the end. Also remember to LOWER your hand, if the question somehow got addressed during the talk. 08:31:50 From Saurabh Srivastav to All panelists : But hBN will be only closed to one graphene layer. In that case, how one can intuitively think of symmetry breaking? 08:35:34 From Eun-Ah Kim - Coordinator to Saurabh Srivastav, All Panelists : Please ask this question during the Q/A by raising the zoom hand now. 08:36:29 From Saurabh Srivastav to All panelists : sure. Thanks 08:38:26 From Andrey Chubukov - Coordinator to All panelists : How a panelist can raise hand? 08:38:49 From Andrea Young - Coordinator to All panelists : Cannot, as far as I can tell--maybe you can just chat to other panelists 08:39:20 From Cory Dean to All panelists : yeah, maybe just send the moderator a direct chat request to ask a question? 08:39:26 From Eun-Ah Kim - Coordinator to All panelists : If you have questions, send me a short private chat. 08:39:37 From Eun-Ah Kim - Coordinator to All panelists : just to tell me that you are “raising hand”. 08:40:01 From Pablo Jarillo-Herrero to All panelists : What about SC? 08:40:10 From Sergio Ulloa to All panelists : Ashvin: many of the features you described are also seen in samples of graphene deposited on engineered substrates (although I’m not aware that superconductivity has been seen yet!). Nadya Mason and Eva Andrei have been playing with these systems, would you comment on what fundamental differences between the physics seen there and they one you talked about? 08:49:05 From Saurabh Srivastav to All panelists : My Internet connection is not stable and probably I miss the chance to ask question. Can someone ask my question? or some expert can resolve my issue. 08:49:38 From Saurabh Srivastav to All panelists : my question is"But hBN will be only closed to one graphene layer. In that case, how one can intuitively think of symmetry breaking? " 08:52:55 From Leon Balents to All panelists : very basic question:does the superconductor then have restored spin/valley symmetry if it is due to skyrmions? 08:53:05 From Julian Ingham to All panelists : I had two questions: (i) could you give a heuristic sketch of the pairing mechanism? (ii) what is the gap symmetry the theory predicts? 08:53:28 From Cenke Xu to All panelists : I am not sure if Ashvin can see this question. Let me ask anyway. If we start with the VBS/plaquette order at the \nu = 2, how many finite temperature phase transitions should there be? Is there an estimate of transition temperature? Which of these transition can potentially lead to a metal-insulator kind of transition? 08:53:32 From Eun-Ah Kim - Coordinator : Please direct questions to Ashvin to the chat window. Please also send any clarification request for Andrea to the chat window. 08:53:59 From Eun-Ah Kim - Coordinator to Cenke Xu, All Panelists : ashvin see the questions since he is a “panelist” as a speaker. 08:55:32 From Allan MacDonald to All panelists : Yes - laughing 09:01:09 From Ashvin Vishwanath : Answer to Cenke’s questions: >If we start with the VBS/plaquette order at the \nu = 2, how many finite temperature phase transitions should there be? you mean K-IVC? There is just one, KT transition, no T breaking ising transition. >Is there an estimate of transition temperature? the stiffness is roughly 10K. >Which of these transition can potentially lead to a metal-insulator kind of transition? if there is no indirect gap - this leads to electron/hole pockets. We often see this in HF, so the order is present its just not able to open a gap everywhere. 09:05:49 From Richa Mitra to All panelists : \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ 09:06:59 From Leon Balents : very basic question:does the superconductor then have restored spin/valley symmetry if it is due to skyrmions? 09:07:16 From Saurabh Srivastav to All panelists : But this nonuniform magnetisation can be due to different local angle as also discussed in different context in cascade phase transition paper? 09:07:25 From Ashvin Vishwanath : Answer to Julian’s questions: >I had two questions: (i) could you give a heuristic sketch of the pairing mechanism? can you access this pdf? https://www.dropbox.com/s/0l28z3x2u7w4x11/kitp-2020slide.pdf?dl=0 >(ii) what is the gap symmetry the theory predicts? There are some caveats but roughly (ignoring spin) it gives a valley singlet (tau_y) fully gapped order. If you include spin its some kind of spin triplet. 09:08:28 From Eun-Ah Kim - Coordinator to Saurabh Srivastav, All Panelists : ok. I will read your question at the end, for sure this time :) 09:08:57 From Babak Seradjeh to All panelists : Shouldn't Andrea still have 12 minutes left? I think we started at :50 for his talk. 09:11:50 From Eun-Ah Kim - Coordinator to Babak Seradjeh, All Panelists : You are CORRECT!! 09:14:50 From Daniel Khomskii to All panelists : This phenomenon is very well known in V2O3: entropy-driven transition with increasing temperature from (Fermi-liquid) metal to paramagnetic insulator with S~ ln2 09:17:52 From Ashvin Vishwanath : Answer to Leon’s question: >>very basic question:does the superconductor then have restored spin/valley symmetry if it is due to skyrmions? I ignored spin but we can talk about valley. indeed in our large N solution valley symmetry is restored (superconductor is valley singlet). In general there could be coexistence phase - skyrmions do not destroy order (condensing merons does) as we noted in our 2004 PRB in the VBS-Neel+Zeeman section. Spin physics is complicated but hopefully this gets most of the question. 09:20:36 From David Perconte to All panelists : Thank you for the very interesting talk. I have a question, what do you think are the ingredients which make superconductivity appear in magic angle twisted bilayer graphene and which are missing in the other systems? 09:21:02 From Ashvin Vishwanath : Answer to Suarabh’s question:But hBN will be only closed to one graphene layer. In that case, how one can intuitively think of symmetry breaking? Thats fine - its sufficient if its on one layer to break symmetry 09:22:17 From Eun-Ah Kim - Coordinator : Please raise your zoom hand if you want to ask in person. Otherwise, if you type the question in the chat window, I will read it for you. 09:22:44 From Herb Fertig to All panelists : To Andrea: In QAH effect Rxy looks beautifully quantized but not exactly at h/e^2. Is it easy to understand why? 09:23:41 From Cory Dean to All panelists : raise hand (if there’s time!) 09:26:00 From Siddharth Parameswaran : We looked at this and the spins modes are gapless with q=2 09:26:09 From Michael Zaletel to All panelists : Andrea: this is partly the relevance of U(4) x U(4) Ashvin discussed 09:26:20 From Yonglong Xie to All panelists : regarding the interpretation of linear T, are you suggesting symmetry breaking for sample with larger twist angle(>2 deg)? 09:26:22 From Siddharth Parameswaran : sorry z=2 09:31:50 From yihang zeng to All panelists : Sorry. I accidentally raised my hand. 09:33:14 From Cenke Xu to All panelists : A general basic comment: if the "fake"/"pseudo" SC behavior is due to the fluctuation and entropy from "magnon" (either spin or pseudospin order), then the \rho(T) curve should be very sensitive to perturbations that suppresses these "magnon" fluctuations, like inplane B, strain, etc. 09:34:29 From Julian Ingham to All panelists : @Ashwin, thanks for the answer - yes I can see the dropbox. Maybe the answer to this is obvious, but what does the coupling n+.n- look like in terms of sigma and tau matrices? Is it something like (sigma^z tau).(sigma^z tau)? 09:35:19 From Siddharth Parameswaran to All panelists : Hey guys, you know you are still broadcasting right? 09:36:40 From Andrea Young - Coordinator to Siddharth Parameswaran, All Panelists : ha, yes we do 09:36:47 From Siddharth Parameswaran to All panelists : Ok, just wanted to make sure 09:39:54 From Kasra Hejazi to All panelists : To Andrea: thanks for your nice talk. What do you think is the reason for the magnetization disorder in the SQUID image? Could sublattice potential disorder also be present? (Different stackings with respect to hBN) 09:53:14 From Andrea Young - Coordinator to Kasra Hejazi, All Panelists : sure! we don't have a good way to figure that out, unfortunately 10:05:35 From Andrea Young - Coordinator : As in the morning session, you can send clarification questions to the panel during the talk, and use the raise hand function in zoom during the Q+A 10:10:13 From Andreas Bill to All panelists : I do not see the slides… Jie Shan seems to have shared the screen but it is black… 10:10:36 From Andrea Young - Coordinator to Andreas Bill, All Panelists : I believe this problem must be on your end--we see them 10:25:46 From charlie johnson : She froze. Is it only me? 10:25:54 From Veit Elser to All panelists : me too 10:25:55 From Siddharth Parameswaran to All panelists : me too 10:25:56 From Julian Ingham : Frozen for me too 10:25:57 From Cory Dean to All panelists : froze for me also 10:26:00 From Liam Cohen to All panelists : same 10:26:04 From Krissia Zawadzki : Here too 10:33:20 From Arup Paul to All panelists : what is the cause of the v like shape around the insulating states in the energy vs vbg plot 10:35:01 From Andrea Young - Coordinator to Arup Paul, All Panelists : Thanks Arup --do you prefer I relay your question or do you want to ask it yourself? If the latter, raise your hand at the end of the talk 10:36:26 From Arup Paul to All panelists : I would like to ask the question. 10:42:56 From Herb Fertig to All panelists : Does this technique allow distinction between intralayer and interlayer excitons? 11:04:35 From Jie Shan to All panelists : Ans to Herb: the different exciton resonances are dispersed into different energy. What I showed is the intralayer exciton in the sensor (the V-shape can be thought of coupling of e-h in the sensor and electron sea in the sample, i.e. interlayer polaron) 11:23:30 From Cenke Xu to All panelists : Thanks Sid! 11:35:03 From bhupesh bishnoi : Hi, Jie, you talk about staggered gap (type 2) WSe2/WS2 hetro structure but due to monolayer and small size quantization effect will it become type 3 broken gap structure specially with voltage of 10V or So in Slide 21..? it usually happen with GaSb/InSb type of 3D bulk semiconductor in nanoscale device..and here most 2D hetro device are nm scale and less atomic dense crystal nd non-equilibrium.. 11:38:52 From Victor Yakovenko to All panelists : if Ashvin is still here, can we hear his story about Skyrmion superconductivity? 11:39:56 From bhupesh bishnoi : yes 11:42:12 From venkatesh chandragiri to All panelists : Hi Jie, thanks for nice talk. I need a clarification on the relation between valley poalrization and susceotibiltiy. Is it spin susceptibility or valley susceptibility..? 11:42:20 From bhupesh bishnoi : okay ma'am.. I though abt it like .5-.7 ev or so in the hetro structure.. so might be small scale quantization 11:42:31 From bhupesh bishnoi : Thank everyone 11:52:40 From Herb Fertig to All panelists : Thank you organizers, great first day. Looking forward to tomorrow.