Oral Session A3 (Tuesday, February 13)
Chair: Surjeet Rajendran, Johns Hopkins University

Special Session Talk
16: 00 - 16 : 40

Maria A. H. Vozmediano
Instituto de Ciencia de Materiales de Madrid (ICMM - CSIC)

Quantum field theory aspects of Diracsemimetals
After the synthesis of graphene (massless Dirac fermions in (2+1) dimensions), Weyl semimetals
emerged as physical realization chiral particles in (3+1) dimensions. Although they can be seen as
3D graphene, a series of new phenomena arise from the fundamental diﬀerences between chiralfermions in two and three dimensions. Chiral imbalance in 3D implies a set of anomaly relatedtransport phenomena first discussed in the context of high energy collisions (quark-gluon plasma).
In particular, quantum anomalies - most prominently the chiral anomaly - have provided a novel
theoretical frame for the understanding of new magneto transport features in Weyl semimetals.
More recently thermal transport has taken the lead in relation with the gravitational anomaly [1,2].
In this talk I will describe some of the aspects of the cross-fertilization between condensed matter,particle physics and gravity. I will try to be pedagogical.
References[1] “Thermal transport, geometry, and anomalies", M. N. Chernodub, Y. Ferreiros, A. G. Grushin, K.
Landsteiner, M. A. H. Vozmediano", Physics Reports 977 (2022) 158.
[2] Generation of a Nernst current from the conformal anomaly in Dirac and Weyl semimetals, Maxim N.
Chernodub, Alberto Cortijo, and M. A. H. Vozmediano, Phys. Rev. Lett. 120, 206601 (2018).

Oral Session A3 (Tuesday, February 13)
Chair: Surjeet Rajendran, Johns Hopkins UniversitySpecial Session Talk
16: 40 - 17 : 20

Naoki Yamamoto
Department of Physics, Keio University

Chiral transport in the universe
In many-body systems of relativistic chiral fermions, unusual transport phenomena emerge due tothe spin-momentum locking and resulting nontrivial Berry curvature. These chiral transportphenomena may appear in various physical systems, such as Weyl/Dirac semimetals, quark-gluon
plasmas in relativistic heavy-ion collisions, electroweak plasma in the early universe, and neutrino
matter in core-collapse supernovae. In this talk, we discuss how these chiral transport phenomena
are relevant in astrophysical and cosmological systems, especially in core-collapse supernovae [1,2].
References[1] K. Kamada, N. Yamamoto, and D. L. Yang, Prog. Part. Nucl. Phys. 129, 104016 (2023)[2] N. Yamamoto and D. L. Yang, Phys. Rev. Lett. 131, 012701 (2023)

Oral Session A3 (Tuesday, February 13)
Chair: Surjeet Rajendran, Johns Hopkins University

Contributed Oral
17: 20 - 17: 40

Chiral anomalies through laser-induced chiral gauge fields
in disordered 3D Dirac semimetals
Hung-Hsuan Teh, Tokiro Numasawa, and Takashi Oka
The Institute of Solid State Physics, The University of Tokyo, Chiba, Japan

Inspired by a recent experiment that observed a significant photoexcited surface current in bismuth
semimetal, we consider a Dirac semimetal subjected to a gradient chiral gauge field. The chiral gauge
field, which can be generated for instance by circularly polarized light (CPL), is known to separate a
Dirac fermion into a Weyl pair, leading to an appearance of Fermi arc states. Our study reveals that,due to the gradient, which can be achieved through the skin eﬀect of the CPL on the semimental
surface, one of the Fermi arc states leaks into the bulk, becoming a delocalized chiral Landau levelstate. We then introduce a homogeneous disorder and find that remarkably the chiral Landau levelstate exhibits greater robustness against scattering than the Fermi arc state, resulting in distinct
lifetimes for two chiral states. Exploiting this asymmetry, we demonstrate an emergence of finite
anomalous current, all without applications of external electric and magnetic fields. This discovery
also serves as a realization of non-Hermitian topological quantum field theory within materials.

17: 40 - 18: 00

Emergent spin-momentum locking and triplet-mixed
cooper pairs in a chiral organic superconductor
Takuro Sato1, 2, and Hiroshi M. Yamamoto1, 2, 3

1. Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Myodaiji, Okazaki, Aichi,444-8585, Japan.
2. The Graduate University for Advanced Studies, Myodaiji, Okazaki, Aichi, 444-8585, Japan.
3. Quantum Research Center for Chirality (QuaRC), Institute for Molecular Science, Myodaiji, Okazaki, Aichi 444-8585,Japan,Chirality is a novel source of several asymmetrical charge/spin transports such as electrical magnetochiral anisotropy(EMChA)[1] and chirality-induced spin selectivity (CISS)[2]. Especially, CISS gives a significant spin-rectificationeven at room temperature despite the negligible spin-orbit coupling (SOC) in organics, which distinguishes it fromEdelstein eﬀect that assumes large SOC from heavy elements. Both CISS and EMChA are distinct manifestationsof chirality-induced spin/charge rectification eﬀects and moreover share a similar parity-time symmetry, stronglysuggesting the intimate relationship between them [Figs. 1(a, b)]. This issue, however, remains a fundamental openquestion.

Oral Session A3 (Tuesday, February 13)
Chair: Surjeet Rajendran, Johns Hopkins University

Here we experimentally address the issue by reporting a gigantic EMChA in a chiral organic superconductor,
κ-(BEDT-TTF)2Cu(NCS)2, that exhibits a giant CISS eﬀect as well [3]. Our study also reveals chiralsuperconducting diode eﬀect and two-gap superfluid in the same device, suggesting a strong hedgehog-typespin-momentum locking and the triplet-mixed Cooper pairs as a common origin for both giant CISS andEMChA [Fig. 1(c)]. We anticipate that a similar strong spin-momentum locking in molecular orbitals can bealso explored to rationalize high spin polarization in molecular CISS eﬀect. The revealed triplet-mixed Cooper
pair in chiral material may play roles in future developments of high critical field superconductors as well as
novel types of quantum computers.
References[1] G. L. J. A. Rikken, et al, Phys. Rev. Lett. 87, 236602 (2001).
[2] R. Naaman, and D. H. Waldeck, J. Phys. Chem. Lett. 3, 2178–2187 (2012).
[3] R. Nakajima, et al, Nature 613, 479–484 (2023).