Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session PP10: V: Popular Physics |
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Sponsoring Units: FIAP Chair: Thomas Meitzler, United States Army Tank Automotive Research, Development and Engineering Center Room: Virtual Room 10 |
Tuesday, March 21, 2023 9:00AM - 9:12AM |
PP10.00001: Should the American Physical Society be more or less welcoming to analysis of underlying data? Jorge E Hirsch There has recently been controversy on whether a reported finding of room temperature superconductivity [1], a holy grail of condensed matter physics, involved data fabrication, alteration and/or manipulation [2]. For over a year, authors refused to provide the underlying data. Preprints reporting technical analysis of the data indicating data fabrication, alteration and/or manipulation were blocked from arxiv and other preprint servers [3]. Papers submitted to journals on this topic were rejected even with unanimously positive referee reviews, on grounds that the papers could bring about legal actions against the journal. In connection with this controversy, the sole statement from APS was [3] "the superconductor controversy may stem in part from the ethos of physics, which has historically encouraged combativeness. “The culture of physics is one that is more aggressive and not very welcoming,"". Requests to APS to intervene in this issue were ignored. In this talk I will argue that APS should be more actively involved in issues concerning scientific integrity, for the benefit of the worldwide physics community and the public. |
Tuesday, March 21, 2023 9:12AM - 9:24AM |
PP10.00002: The long march to silicene and germanene Guy Le Lay At the origin of all artificial graphene-like two-dimensional mono-elemental materials, coined Xenes, is the seminal, totally iconoclastic, paper of Takeda and Shiraishi, who predicted already in 1994 the ‘Theoretical possibility of stage corrugation in Si and Ge analogs of graphite’, in other words, the possible existence of freestanding silicene and germanene in a so-called low-buckled honeycomb geometry, at variance with graphene, which is nominally flat. Silicene was synthesized and presented for the first time at the 2011 APS March meeting in Dallas. After a gold rush, germanene, the second xene, was obtained in 2014, exactly ten years after the advent of graphene. Then a cornucopia of other xenes from borophene to tellurene appeared in succession. Yet, a signature of germanene was already encrypted in a 1971 thesis, but it remained undeciphered and unpublished for more than half a century. Here, the saga of of silicene and germanene, from the dark ages to the limelight will be narrated. |
Tuesday, March 21, 2023 9:24AM - 9:36AM |
PP10.00003: Bruno Touschek and the birth of collider physics: an extraordinary journey Giulia Pancheri-Srivastava I will describe new findings about the Austrian born scientist Bruno Touschek, who in 1960 proposed and built in Italy the first ever electron-positron collider. A recently published biography and the Proceedings of a Memorial Symposium, held in Rome in December 2021 one hundred years after his birth in Vienna on 3 February 1921, highlight Touschek’s scientific work and the three particle accelerators he brought to success, from Rolf Wideroe’s betatron in 1944, to the e+e- colliders AdA and ADONE in the 1960’s. Touschek’s life spanned Europe in space and time, from racial discrimination, because his mother was Jewish, to the years of European reconstruction. After escaping deportation to the Kiel concentration camp in April 1945, Touschek pursued his studies in Goettingen, where he was Heisenberg’s assistant in 1946, and in Glasgow, where he was befriended by Max Born, and received his PhD, with Rudolf Peierls as external examiner. Arriving in Italy in the early 1950s, he learnt the CPT theorem from Wolfgang Pauli and envisioned its consequences in his proposal to build the world’s first matter-antimatter storage ring in Frascati, becoming one of the leading figures in the development of electron-positron colliders in the 1960’s. |
Tuesday, March 21, 2023 9:36AM - 9:48AM |
PP10.00004: Genesis of a Quantum Impedance Model: It's Piledrivers all the way down peter cameron A mechanical analog of the Dirac equation can be found in the vibratory piledriver, a device comprised of two identical counter-rotating eccentric weights, transforming 2D rotational motion into 1D translation, the eccentrics corresponding to Dirac electron and positron spinors counter-rotating in phase space. Mass is quantized in quantum mechanics. Given a logically rigorous analysis of background independance and Mach's principle in the piledriver, quantized mechanical impedance networks are easily calculated, and easily transformed to electromagnetic via the electromechanical oscillator. This is important. Impedance matching governs amplitude and phase of energy transmission in QED wavefunction interactions. This presentation will outline the concept and history of impedance matching, how it got lost in quantum mechanics, and how it opens new windows within the standard models of particle physics and cosmology via the minimally (and maximally) complete geometric Clifford algebra representation of string theory vacuum wavefunctions. |
Tuesday, March 21, 2023 9:48AM - 10:00AM |
PP10.00005: Knowledge Holds Up the Universe Douglas M Snyder Classical em theory holds that as a charge accelerates it emits em radiation. As it loses energy, the electron’s orbit moves closer to the nucleus. As the electron continues to accelerate, the electron loses enough energy so that it crashes into the nucleus. This does not occur. One reason the universe exists around us is because in non-relativistic quantum mechanics the Schrodinger equation provides the correct description of what are generally called particles. When one solves this equation, one finds that there are discrete wave functions associated with specific energy levels for electrons bound to the atom and that there is a minimum non-zero energy level for the bound electron for the ground state. Complex in nature, all these functions have real and imaginary parts which provide the basis for probabilistic predictions (knowledge) with no deterministic physical reality underlying these functions. Also, the electron doesn’t lose energy though described by an angular momentum operator that would indicate that the electron is accelerating in its orbit around the nucleus. The reason lies in the wave functions for the electrons. Bound electrons have standing wave functions. When you take the absolute square of the wave function for any infinitesimal distance, the probabilities do not change. If the probabilities do not change, the energy density associated with any infinitesimal distance along the wave function is constant. The electron does not lose energy over time. Knowledge holds up the universe. |
Tuesday, March 21, 2023 10:00AM - 10:12AM |
PP10.00006: Structural engineering methods to combine the diaphragm and cantilevers for flexible capacitive pressure sensor Nazek El-Atab, Rishabh B Mishra, Fhad Al-Modaf, Wedyan Babatain, Aftab Hussain Structural engineering provides enormous support to the design and analysis of sensitivity enhancement and optimisation of flexible sensors. Including that, the household materials are playing a vital role in democratising the electronics/robotics. We have utilised these materials to perform structural engineering approach to design the flexible capacitive pressure sensor for 1-20 kPa operational range. Different modal analysis with different number of cantilevers at the edges of the circular and square shaped diaphragms are presented. Initially, we performed finite element of analysis of all possible designs. For further sensitivity enhancement, we changed the shape of cantilevers from rectangular to isosceles trapezium and connected the small side of trapezium to the diaphragms. The sensors are fabricated using aluminium coated polyimide foil, double sided tape and posted paper. We have utilized the Versa 2000 carbon dioxide laser to cut these foils and further utilised the DIY-fabrication techniques. We performed the experimental investigation of all the possible designed using air pressure and acoustic pressure monitoring set-up. |
Tuesday, March 21, 2023 10:12AM - 10:24AM |
PP10.00007: Chemical vapor deposition and thermal stability of two-dimensional Pb-Sn binary-metal perovskite thin films Christopher J Arendse, Siphesihle S Magubane, Randy Burns, Suchismita Guha 2D-metal halide perovskites have attracted considerable attention, mainly due to its unique opto-electronic properties and exceptional stability in an ambient environment. This has significant implications for its application in solar cells with long-term operational stability. Global regulations on the use of toxic elements in industrial products requires a lead (Pb)-reduction in perovskite solar cells. Tin (Sn) is the preferred candidate as a replacement for Pb, since it meets the ionic size, coordination and charge balance requirements. The 2D perovskites can be grown by a variety of techniques, of which chemical vapor deposition (CVD) is favorable in terms of scalability and repeatability. Large cation constituents; e.g. phenethylammonium iodide (PEAI), are used to produce 2D phenethylammonium lead iodide (PEA2PbI4). We report on a 3-step CVD process for the deposition of a 2D Pb-Sn perovskite thin film, where the conversion temperature (from the binary-metal halide to the perovskite) is optimized at 100 °C, as confirmed by the well-defined grain boundaries and the characteristic exciton absorption and emission features. Furthermore, photoluminescence measurements from 20 – 300 K confirm the improved optical and structural stability of the single-metal films (Pb or Sn only), which is attributed to the size effect of the PEA molecule. Lastly, we will report on the electron-phonon interaction of the 2D Pb-Sn perovskite layer. |
Tuesday, March 21, 2023 10:24AM - 10:36AM |
PP10.00008: Self-powered Near-infrared Organic Photodiode with Functional Interlayer Yongju Lee, Hyowon Jang, Biswas Swarup, Hyeok Kim The electromagnetic spectrum consists of ultraviolet (100-400 nm), visible (400-750 nm), and infrared (750-2500 nm) regions, among others. When the light released from any source or heating element is spectrally scattered, infrared light is outside the red edge of this band and belongs to the visible region, which contains the wavelengths that can be perceived by the human eye, The electromagnetic waves in the infrared spectrum with the shortest wavelength are known as near-infrared rays (750 – 1000 nm). Here, an organic photodiode was fabricated that can sensing light in the near-infrared wavelength band by bandgap matching the photoactive polymer for near-infrared. In addition, the organic photovoltaic was optimized through a newly synthesized functional interlayer; this layer constitutes a hole-transport layer that transfers the holes generated by the photoactive layer to the cathode easily. The material that is typically utilized for the hole transport layer is PEDOT:PSS, which has excellent heat resistance, high electrical conductivity, and transparency as advantages. However, PEDOT:PSS has drawbacks such high hydrophilicity, strong acidity, and inefficient cost. We synthesized a PPY:PSS as a hole-transport material that overcomes these drawbacks, and we optimized hole transport material by adjusting the ratio of PPY to PSS. As a result, by adding the new functional interlayer, an organic photodiode that can sense in the near-infrared range more efficiently was fabricated. |
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