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Condensed matter seminar

Fundamentals of Entangled Probes for Entangled Matter

Advancing the frontiers of science often requires the creation of new probes to uncover the
underlying microscopic mechanisms giving rise to exotic macroscopic phenomena, such as high-
temperature superconductivity. Can quantum entangled probes uncover the inherent
entanglement of the target matter? We have recently [1-3] developed an entangled neutron
beam where individual neutrons can be entangled in spin, trajectory, and energy. To
demonstrate entanglement in these beams we crafted neutron interferometric measurements
of contextuality inequalities whose violation provided an indication of the breakdown of
Einstein's local realism. In turn, the tunable entanglement (spin-echo) length of the neutron
beam from nanometers to microns and energy differences from peV to neV opens a pathway to
a future era of entangled neutron scattering in matter. What kind of information can be
extracted with this novel entangled probe? A recent general quantum many-body entangled-
probe scattering theory [4] provides a framework to respond to this question. Interestingly, by
carefully tuning the probe's entanglement and inherent coherence properties, one can directly
access the intrinsic entanglement of the target material. This theoretical framework supports
the view that our entangled beam can be used as a multipurpose scientific tool. We are
currently [5] pursuing several ideas and developing new spin-textured entangled beams with
OAM for future experiments in candidate quantum spin liquids, unconventional
superconductors, and chiral quantum materials.

[1] J. Shen et. al., Nature Commun. 11, 930 (2020).
[2] S. Lu et. al., Phys. Rev. A 101, 042318 (2020).
[3] S. J. Kuhn et. al., Phys. Rev. Research 3, 023227 (2021).
[4] A. A. Md. Irfan, P. Blackstone, R. Pynn, and G. Ortiz, New J. Phys. 23, 083022 (2021).
[5] Q. Le Thien, S. McKay, R. Pynn, and G. Ortiz, arXiv:2207.12419.

Date:
Location:
Chemistry-Physics Bldg. Room 179
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Topological Gravitational Response: Novel physics, principles and predictions

What physics does one hope to learn by looking closely at exotic quantum states of matter, esoteric to begin with, but even more so on curved surfaces?! In this talk first I will remind the audience why quantum hall states serve as paradigmatic topological quantum states of matter, highlighting their signature property: the quantization of Hall conductance, which is independent of sample-specific details to the extent that it is used for precise measurements of fundamental constants. Tracing the topological origin of this remarkable property, I will motivate by analogy the interplay between the geometry of these states and their response to “gravitational” perturbations, i.e., deformations to the real space manifold they are embedded in — on a cone, for example! This then naturally leads to a discussion of what, if any, universal signatures characterize this response. Finally, some reflections on the broader implications of these excursions, and connections to other branches of physics, including classical soft matter systems.

Short bio:
Dr. Biswas received his PhD from Harvard University, working with Prof. Subir Sachdev on experimentally relevant exotic quantum states of matter.  Prof. Bert Halperin served as mentor. While at Harvard Rudro held several fellowships including the James Mills Pierce Fellowship Award, the Purcell Fellowship and the Harvard Center for Energy and Environment Fellowship. Following postdoctoral research as an Institute of Condensed Matter Theory Fellow at UIUC, Rudro became an Assistant Professor of Physics at Purdue University, where he is currently.

 

Date:
Location:
Chemistry-Physics Bldg. Room 179
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Carbon Based Nano Electromechanics: Physics and Applications

Carbon Based Nano Electromechanics: Physics and Applications
 
Sang Wook Lee
 
Department of Physics, Ewha Womans University, Seoul, 03760, Korea
 
In this presentation, physical properties and possible applications of carbon based nano electro-mechanical devices
(NEMS) will be introduced. Our research started from carbon nanotube based nano electro-mechanical relay
structure and expanded to graphene-based xylophone and drum like devices. Micro contact transfer method is
applied to realize the suspended nano structures with various electrodes under the nano materials. Recently
developed pick-up and transfer technique made us possible to fabricate various stacking and suspended nano
structures. After introducing some interesting physical properties, such as basic mechanical switching and
resonance behaviour and light emission of suspended graphene structures, possible application of carbon based
nano electro-mechanical devices will be suggested. Graphene based ultra-sensitive mass detector will be suggested
for one of the promising applications of our devices and our recent research project on single protein sequencing
using graphene-based mass detector will be introduced at the end of presentation.
Date:
Location:
Chemistry-Physics Bldg. Room 179
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