|speaker||Prof. Adolfo del Campo (UMass Boston)|
|title||Engineering Quantum Thermal Machines|
Quantum thermodynamics has emerged as an interdisciplinary research field in quantum science and technology with widespread applications. Yet, the identification of scenarios characterized by quantum supremacy - a performance without match in the classical world - remains challenging. In this talk I shall review recent advances in the engineering and optimization of quantum thermal machines. I will show that nonadiabatic many-particle effects can give rise to quantum supremacy in finite-time thermodynamics . |
Tailoring such nonadiabatic effects by making use of shortcuts to adiabaticity, quantum heat engines can be operated at maximum efficiency and arbitrarily high output power . A thermodynamic cost of these shortcuts will be elucidated by analyzing the full work distribution function and introducing a novel kind of work-energy uncertainty relation . I shall close by discussing the identification of scenarios with a quantum-enhanced performance in thermal machines run over many cycles .
 J. Jaramillo, M. Beau, and A. del Campo, New J. Phys. 18, 075019 (2016).
 M. Beau, J. Jaramillo, and A. del Campo, Entropy 18, 168 (2016).
 K. Funo, J.-N. Zhang, C. Chatou, K. Kim, M. Ueda, and A. del Campo, Phys. Rev. Lett. 118, 100602 (2017).
 G. Watanabe, B. P. Venkatesh, P. Talkner, and A. del Campo, Phys. Rev. Lett. 118, 050601 (2017).
|speaker||Prof. Haruki Watanabe (UTokyo)|
 H. Watanabe, H. C. Po, A. Vishwanath, and M. P. Zaletel, Proc. Natl. Acad. Sci. U.S.A. 112, 14551 (2015); H. C. Po, H. Watanabe, C.-M. Jian, and M. P. Zaletel, arXiv:1703.06882. 日本物理学会誌 2017年1月号に解説あり。
 H. Watanabe, H. C. Po, M. P. Zaletel, and A. Vishwanath, Phys. Rev. Lett. 117, 096404 (2016); H. C. Po, H. Watanabe, M. P. Zaletel, and A. Vishwanath, Sci. Adv. 2, e1501782 (2016); H. C. Po, A. Vishwanath, and H. Watanabe, Nat. Commun. 8, 50 (2017); H. Watanabe, H. C. Po, and A. Vishwanath, arXiv:1707.01903.
|speaker||Flore K. Kunst (Stockholm University / Freie Universitat Berlin)|
|title||Anatomy of Topological Flat and Surface States: Exact Solutions from Destructive Interference on Frustrated Lattices|
|abstract||The main feature of topological phases is the presence of robust boundary states, which appear for example in the form of chiral edge states in Chern insulators and open Fermi arcs on the surfaces of Weyl semimetals. Even though, non-interacting, topological systems can be straightforwardly described in fully periodic systems, the detail of the corresponding boundary states has mainly relied on numerical studies. In our work, we present a general method on how to find exact, analytical solutions for topological as well as trivial boundary states using a generic tight-binding model on a large class of geometrically frustrated lattices without the necessity of having to fine-tune hopping amplitudes. Our method is inspired by a similar approach that has been used in the past to construct, topologically-trivial, flat band models from local constraints on ‘line graphs’, in which case fine-tuning is required in the sense that hopping is strictly local. We expand on this work by considering a larger class of lattices, finding solutions for both topologically trivial and non-trivial bands, and going beyond the need for fine-tuning. In this sense, it is likely that our work will contribute to both the research fields of flat-band physics and that of topological matter, as well as advance the cross-fertilization between them. In my talk, I will present a number of examples to illustrate our discoveries, some of which are experimentally relevant such as the derivation of exact solutions for Fermi arcs in the recently synthesized slabs of pyrochlore iridates.|
|speaker||Dr. Emil J. Bergholtz (Stockholm University / Freie Universitat Berlin)|
|title||Fractional Chern insulators: From higher Chern number phases to non-Abelian twist defects|
|abstract||In this talk I will discuss fractional Chern insulators with emphasis on the analogy with more conventional continuum Landau level physics — and on aspects that are qualitatively new in the lattice setting such as Berry curvature fluctuations, competing instabilities and novel collective states of matter emerging in bands with higher Chern number. I will also explain how the lattice setting naturally allows for exotic extrinsic wormhole-like twist defects (aka “genons”) that effectively increase the genus of space.|