Bulletin of the American Physical Society
Joint Fall 2017 Meeting of the Texas Section of the APS, Texas Section of the AAPT, and Zone 13 of the Society of Physics Students
Volume 62, Number 16
Friday–Saturday, October 20–21, 2017; The University of Texas at Dallas, Richardson, Texas
Session B6: General Physics I |
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Chair: Bing Lv, University of Texas at Dallas Room: DGAC 1.135 |
Friday, October 20, 2017 2:45PM - 2:57PM |
B6.00001: Using Lidar Information to Help Safety First Responders Yash Gandhi, Vihang Jani, Jeb Benson In emergencies, many public safety personnel die within a few feet of safety. Lidar can be used to create a dynamic map of an area. When Lidar data is combined with a simultaneous localization and mapping algorithm, the result can be used to help safety first responders navigate through a number of dangerous environments. This talk will describe the details of such a system. [Preview Abstract] |
Friday, October 20, 2017 2:57PM - 3:09PM |
B6.00002: Local Hidden-Variable Model for a Recent Experimental Test of Quantum Nonlocality and Local Contextuality Brian La Cour An experiment has recently been performed to demonstrate quantum nonlocality by establishing contextuality in one of a pair of photons encoding four qubits; however, low detection efficiencies and use of the fair-sampling hypothesis leave these results open to possible criticism due to the detection loophole. In this talk, a physically motivated local hidden-variable model is described as a possible mechanism for explaining the experimentally observed results. The model, though not intrinsically contextual, acquires this quality upon post-selection of coincident detections. [Preview Abstract] |
Friday, October 20, 2017 3:09PM - 3:21PM |
B6.00003: Quantum-Classical Correspondence through the Momentum Function M.K. Balasubramanya Quantum Hamilton-Jacobi theory formulated in terms of the quantum characteristic function leads to the definition of the quantum momentum function. As in classical mechanics where the dynamical equations lead to trajectories in phase space quantum mechanics points to paths in complex phase space for stationary states. The relation between the coordinate and the momentum displays a rich structure with the momentum function riddled with poles each of which has a residue proportional to Planck's constant. For high excitations the quantum momentum function transitions to the classical momentum function leading to the orbit equation in phase space. The mechanism of this transition will be illustrated for a few analytic potentials. [Preview Abstract] |
Friday, October 20, 2017 3:21PM - 3:33PM |
B6.00004: The Sagnac Effect and the Ritz Theory James Espinosa, James Woodyard The Sagnac experiment was performed in 1913 to prove the existence of the aether; it consists of sending two beams of light in opposite directions in a closed loop which is rotated around its central axis producing a shift in the observed fringes. Its positive results were interpreted by the physics community as support for Einstein's theory of relativity and a further blow to aether theories. In 1960, Fox revived an interest in an alternative theory created by Walter Ritz in 1908 which remained within the framework of Newtonian mechanics. Ritz's theory had been viewed as discredited by experiments such as Fizeau and Sagnac. He concluded that with the introduction of a modification mentioned in Ritz's notes, which Fox called the extinction theorem, these experiments were now explained by Ritz also. In the early 21$^{\mathrm{st}}$ century, several Russian physicists have revived the original proposal of Ritz and have been reminded by Malykin of the futility of this approach with regard to the Sagnac effect. After a short description of the experiment of Sagnac, we will present a modified Ritz theory that has overcome the objections of Fox with regard to fast moving sources and apply this recent approach to the Sagnac effect. [Preview Abstract] |
Friday, October 20, 2017 3:33PM - 3:45PM |
B6.00005: Introduction to paths H and application of homotopy theory in physics Fidele Twagirayezu Firstly, we introduced the action of space operators on a regular interval to generate a variable interval. Secondly, we introduced the concept of a family T of paths H, and we showed that these paths are homotopic on a contractible space even though they do not have common endpoints. Finally, we applied the concept of paths H on a contractible space in physics. Let A be a subset of X. Let I$_{\mathrm{\{a,b\}\thinspace }}$be a regular interval such that \textbraceleft I$_{\mathrm{\{a,b\}}}$\textbraceright $\subseteq $ A, for a, b $\in $ A. Let ($\alpha_{\mathrm{a}}$,$_{\mathrm{\beta \thinspace b}})$ be space operators associated with\textbraceleft a,b\textbraceright , then a variable interval is I$_{\mathrm{\{x,y\}}}=(\alpha_{\mathrm{a}}$,$\beta _{\mathrm{\thinspace b}})$I$_{\mathrm{\{a\thinspace ,b\}}}$ such that \textbraceleft I$_{\mathrm{\{x,y\}}}$\textbraceright $\subseteq $ X, min\textbraceleft I$_{\mathrm{\{x,y\}}}$\textbraceright $=$ax, and max\textbraceleft I$_{\mathrm{\{x,y\}}}$\textbraceright $=$by for all x, y $\in $X. Let X be a topological space. Let f, g: [0,1] $\to $X be continuous paths for all t $\in $ [0,1]. T is the family of continuous paths H: [0,1]x[0,1]$\to $ X such that H(t,0)$=$f, H(t,1)$=$g for all t $\in $ [0,1], and H(0,s$_{\mathrm{f}})=$f(0), H(1,s$_{\mathrm{f}})=$f(1), H(0, s$_{\mathrm{g}})=$g(0), H(1,s$_{\mathrm{g}})=$g(1) for all s$_{\mathrm{f,\thinspace }}$s$_{\mathrm{g\thinspace \thinspace }}\in $ [0,1]. Such f and g are H-topic paths. If X is contractible, then H is a homotopy. In addition, if s$_{\mathrm{f}}=$s$_{\mathrm{g}}$, then f(0)$=$g(0) and f(1)$=$g(1), and the family T of paths H becomes the well-known homotopy of paths (with same endpoints). Let M$_{\mathrm{G}}$ be a simply connected gravitational field. We showed that the Hamiltonian for free fall-paths on M$_{\mathrm{G}}$ obeys the homotopy theory. [Preview Abstract] |
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