Events
Condensed Matter Seminar
Topology and transport in inversion asymmetric crystals
Shuichi Murakami
Mon, 25 Mar 2019, 11:30
Sacta-Rashi Building for Physics (54), room 207
Abstract: When a crystal lacks spatial inversion symmetry, it sometimes allows novel band structures and transport properties which are absent in inversion-symmetric crystals. For example, Weyl semimetals [1], which have Dirac cones in the band structure near the Fermi energy, are allowed in inversion asymmetric crystals, and they actually emerge in a universal way. We showed that a Weyl semimetal phase always appears in a transition between topological and ordinary insulators for any inversion-asymmetric crystals [1]. Moreover, if the gap of an inversion-asymmetric system is closed by a change of an external parameter, the system runs either into a Weyl semimetal phase or a nodal-line semimetal [2]. It is realized e.g. in tellurium (Te). Tellurium consists of helical chains, lacking inversion symmetry. At high pressure the band gap of Te closes and it runs into a Weyl semimetal phase, as shown by our ab initio calculation [3].
In such inversion asymmetric crystals, we propose that the current induces an orbital magnetization, and we call this effect an orbital Edelstein effect. For example, in tellurium where the crystal consists helical chains, a current along the helical axis induces an orbital magnetization [4-5], as is analogous to classical solenoids. Moreover, a similar effect appears for phonons. Each phonon eigenmode has angular momentum due to rotational motions of the nuclei, but their sum is zero in equilibrium. Meanwhile a heat current in the Te crystal induces a nonzero total angular momentum [6], which we call phonon thermal Edelstein effect.
1. S. Murakami, New J. Phys. 9, 356 (2007).
2. S. Murakami, M. Hirayama, R. Okugawa, S. Ishibashi, T. Miyake, Sci. Adv. 3, e1602680 (2017).
3. M. Hirayama, R. Okugawa, S. Ishibashi, S. Murakami, and T. Miyake, Phys. Rev. Lett. 114, 206401 (2015).
4. T. Yoda, T. Yokoyama, and S. Murakami, Sci. Rep. 5, 12024 (2015).
5. T. Yoda, T. Yokoyama, and S. Murakami, Nano Lett. 18, 916 (2018).
6. M. Hamada, E. Minamitani, M. Hirayama, S. Murakami, Phys. Rev. Lett. 121, 175301 (2018).
Particles and Fields Seminar
Fits and predictions of the HISH (holography inspired stringy hadron) model
Cobi Sonnenschein
Mon, 25 Mar 2019, 14:00
Sacta-Rashi Building for Physics (54), room 207
Abstract: I will briefly describe the HISH model. I will then describe the fits of the model to PDG data and present predictions for yet unobserved states. This will include: (i) the spectra of mesons and baryons, (ii) identification of glueballs (iv) exotic tetra quark states (v) the total and partial decay width of any kind of hadron.
Physics Colloquium
Moving High-Energy Nuclear Physics Forward at the LHC: A Heavy-Ion-Centric Perspective on the Near Future at the LHC
Zvi Citron
Tue, 26 Mar 2019, 15:30
Ilse Katz Institute for Nanoscale Science & Technology (51), room 015
Abstract: At the Large Hadron Collider (LHC), collisions of heavy ions achieve such an extremely high energy density that a thermalized medium of quarks and gluons, a Quark Gluon Plasma (QGP), is produced. Over the last several years, the heavy ion program at the ATLAS experiment (at the LHC) has achieved great success studying heavy-ion collisions and characterizing the QGP. In addition to the study of the QGP in heavy-ion collisions there has been a surprising observation of QGP-like signatures even in smaller collisions systems - pp and pA - which were not previously expected to produce a QGP. This result has forced the reconsideration of longstanding assumptions in the field and its full consequences are still under active exploration. The QGP program described above has focused primarily on hadronic collisions observed at mid-rapidity with forward rapidity measurements playing only a supporting role. Recently, interest has grown in forward rapidity measurements for identification of non-hadronic and semi-hadronic events, and this requires upgrading detector capabilities.
Measurements of interest in QGP studies and beyond, as well as plans for upgrading the detector, in particular a radiation hard photon and neutron detector for forward rapidity, will be presented.
Refreshments are served at 15:15.
Astrophysics and Cosmology Seminar
What planet formation tells us about planetary interior structure
Allona Vazan
Wed, 27 Mar 2019, 11:10
Sacta-Rashi Building for Physics (54), room 207
Abstract: Thousands of extrasolar planets have been discovered in our galaxy in the last decades, and the number continues to grow. These discoveries raise fundamental questions about formation, composition and structure of planets. In order to better understand interior structure of planets we have to link it to the planet formation history. Planet interior models usually assume 2-3 layer structure, mainly for simplicity. However, new planet formation models suggest that the composition is probably gradually distributed during planet formation. Here I present the current planet formation mechanisms, and the resulting planetary structure. I discuss what (and if) we can learn about the current planetary interior from planet formation, and how it differs from the old conventional models.
Condensed Matter Seminar
TBA
Yuval Oreg
Mon, 01 Apr 2019, 11:30
Sacta-Rashi Building for Physics (54), room 207
Abstract:
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