Welcome!
In the Scaffidi group, we study emergent phenomena of quantum matter, including hydrodynamics, quantum chaos, topological matter, superconductivity, and applications to quantum computing. We are part of the Department of Physics and Astronomy at UC Irvine. Some of our group members also have affiliations with the University of Toronto. You can learn more about our research in the Research tab. For a complete list of publications, please see arXiv or Google Scholar.
Working with me
We regularly have openings in my group at the Undergraduate, Master, PhD and Postdoctoral level, please get in touch at firstname.surname@gmail.com.
PhD applicants should apply here, the deadline is December 15.
We currently have an opening for a postdoctoral researcher, apply here before Jan 1st 2024: https://academicjobsonline.org/ajo/jobs/26518
News
June 2024: check out Amin's recent work on entanglement in symmetric maximally-mixed states: https://arxiv.org/abs/2406.08542. Very interesting work Amin!
June 2024: TS will be spending the summer at IST Austria as a visiting professor. Many thanks to ISTA and Maksym Serbyn for making it happen!
March 2024: A few papers from the group appeared in print recently:
Our review on electron hydrodynamics with Lars Fritz is published in Annual Reviews of Condensed Matter Physics, I think it serves as a good intro for students starting to work in this field : ARCMP review
Our work with Omid on a minimal tight-binding model for copper-substituted lead apatite (the infamous LK-99!) appeared in PRB
it's been a lot of fun collaborating with the group of Prof. Javier Sanchez-Yamagishi, also at UCI, on an electron-phonon hydrodynamic instability in graphene. The paper just appeared in Nature Comms.
TS was a coauthor on an experimental study of non-local electrodynamics in PdCoO2 led by Graham Baker, which appeared in PRX
The dual-rail qubit paper from the AWS collaboration appeared in PRX
February 2024: The "snake" paper is published in SciPost Physics, check it out here. Congrats to Amin and Dan! 🐍🐍🐍
January 2024: Congratulations to Omid for his Eddleman Quantum Institute fellowship!
October 2023: If a soup of loops decorated with a 1D SPT give a 2D SPT, what do you get if you decorate loops with a 1D CFT? A: You get a snake soup! See the preprint here
September 2023: Our work on complex conformal field theories in the O(n) model was accepted into PRL. Congratulations, Omid!
August 2023: Along with Zihao Qi and Xiangyu Cao, we have recently introduced the concept of deep Hilbert space (DHS), a useful way to think about various layers of quantum-chaotic dynamics appearing in large-N and large-S systems: check it out on arXiv (and it just appeared in PRB).
August 2023: check out our preprint with Omid Tavakol on a minimal model for the flat bands predicted to appear in copper-substituted lead phosphate apatite.
July 2023: In a recent preprint, we have proposed a mechanism for the intriguing magnetic memory effect in the superconductor 4Hb-TaS2
July 2023: Congratulations to Davis for his outstanding graduate student award!
April 2023: Check out our review on electron hydrodynamics, co-authored with Lars Fritz and to appear soon in Ann. Rev. Cond. Mat. Phys!
March 2023: We have just posted a preprint about complex CFTs hiding in the complex temperature plane of the O(n) loop model. Moral of the story: there is plenty of room in the complex plane!
November 2022: One of my favorite facts about the UC system is that we have a very high percentage of first-generation college students (probably because I am one myself!). First generation college students can experience additional challenges, so it is really inspiring to read about their success stories here.
October 2022: Our work on the conductance of hydrodynamic electrons flowing through a wormhole was just published in PRL! It was also featured in the Journal Club for Condensed Matter Physics with a commentary by Aaron Hui and Brian Skinner.
September 2022: Our work on hydrodynamic electron flows beating the quantum limit of conductance was just published in Nature! See here for a press release, and here for the article. It was also featured in the Journal Club for Condensed Matter Physics with a commentary by Aaron Hui and Brian Skinner.
July 2022: Big news: the group is moving to UC Irvine in September! We have openings at the Undergraduate, Master, PhD and Postdoctoral level, please get in touch by email.
May 2022: An interesting byproduct of the recent interest in hydrodynamic electronic transport has been the discovery of new ballistic effects at low temperatures in ultra-clean crystals. These ballistic effect are even more striking when the Fermi surface is polygonal, like the hexagonal Fermi surface of PdCoO2 (see figure). Our work on this recently appeared in Nature Physics here.
March 2022: Zihao Qi has joined the group as a summer intern, welcome!
February 2022: Haoting Xu has joined the group as a PhD student, welcome!
November 2021: We will have two new group members joining us in January 2022: Amin Moharramipour (PhD student) and Samuel Vadnais (UG student from Sherbrooke). Welcome!
November 2021: In an ongoing experiment-theory collaboration with the groups of Shahal Ilani, Ady Stern, and Andre Geim, we have recently provided (see the preprint here) a demonstration of the geometric origin of the "superballistic" conductance of hydrodynamic electrons described in the post below. The experiment was done with a graphene sample in a Corbino geometry (which is just a disk with a hole in the middle), which is much easier to realize than a wormhole!
November 2021: What is the conductance of a wormhole? Surprisingly, this far-fetched question is directly related to the very practical problem of making small electronic devices with the highest possible conductance. In a recent preprint, we show that, by a judicious choice of geometry, it is possible to reach an arbitrarily large conductance when electrons are a in novel regime of transport called hydrodynamic.
November 2021: The nature of superconductivity in Sr2RuO4 has remained a mystery for more than 20 years now (see here for a review). In an ongoing collaboration with the groups of Clifford Hicks and Andrew Mackenzie, we had previously shown (Science 2017) how in-plane pressure provides a way of drastically changing the superconducting properties of this material, all the way to a van Hove singularity at which the critical temperature more than doubles compared to the unstrained value. Surprisingly, as we show in a recent preprint, out-of-plane pressure lowers Tc instead of increasing it, which is hard to reconcile with most current candidates for the order parameter in this material. The search continues!
March 2021: Good news from two former members of the group! Jack Farrell, who did an NSERC-USRA summer research project in the group on electron hydrodynamics, will start his PhD in condensed matter theory at CU Boulder in the Fall. Qucheng Gao, who visited the group in 2019, will start his PhD in CMT at Boston College. Well done to both of you!
September 2020: When Hartree-Fock recovers 0% of the ground state energy, one has to come up with something else entirely. This is what we did for the Sachdev-Ye-Kitaev models in this preprint.
August 2020: What happens if you try to deform a loop condensate into another loop condensate, but with opposite loop fugacity? Short answer: they form stripes. Long answer: here.
May 2020: Great news! Our group was awarded the Discovery grant and the Discovery Accelerator Supplement grant from NSERC. This will fund our research on the hydrodynamics of quantum systems for the next 5 years.
April 2020: Scrambling = chaos ? Short answer: no. Long answer: here.
Featured in PRL, with a simple sketch which summarizes the paper, by Tianrui Xu =>
October 2019: I recently gave two talks which are available online: a colloquium about electron hydrodynamics at U of T, and a seminar about operator complexity and quantum chaos at the Perimeter Institute.
October 2022: Our work on the conductance of hydrodynamic electrons flowing through a wormhole was just published in PRL! It was also featured in the Journal Club for Condensed Matter Physics with a commentary by Aaron Hui and Brian Skinner.