Bulletin of the American Physical Society
APS April Meeting 2019
Volume 64, Number 3
Saturday–Tuesday, April 13–16, 2019; Denver, Colorado
Session Z13: General Physics |
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Sponsoring Units: DGRAV Room: Sheraton Plaza Court 2 |
Tuesday, April 16, 2019 3:30PM - 3:42PM |
Z13.00001: Spin dynamics of walkers in a rotating bath Akshunna S Dogra We investigate a hydrodynamic analog system exhibiting wave-mediated interactions of spins in a rotating frame. Liquid droplets ('walkers') may walk across a vertically vibrating liquid surface, propelled by resonant interactions with their own wavefield. Their trajectories can be trapped within the surface of submerged circular wells in a fluid bath, locked into orbits centered around the wells. We study a system where these wells are arranged in a 1D lattice, with thin fluid layers allowing interactions between neighboring walkers. Let the bath be rotating with some velocity 'w'. We use the Preisach model to forward a mathematical framework that explains why individual walkers tend towards aligning with the polarity of the rotating bath (Sáenz et. al., Phys. Rev. Fluids 3, 100508). Our model defines the hydrodynamic analogs of remanence, coercivity and energy loss over a cycle, as is common in magnetic hysteresis studies and predicts their expected values. We predict that the dependence of the averaged spin (S) on 'w' mirrors that of the magnetization of a ferromagnet in an external magnetic field. Lastly, we show how the evolution of spin of a single walker in a rotating bath should be expected to mirror that of a solitary magnetic dipole's moment in a magnetic field. |
Tuesday, April 16, 2019 3:42PM - 3:54PM |
Z13.00002: Atomic Layer Deposition for Improving Surface Roughness of Microfluidic Injectors for XFEL and Synchrotron Sample Delivery Lars Paulson†, Sankar Raju Narayanasamy†, Martin Trebbin Recent advances in additive manufacturing, such as two-photon polymerization (3D-2PP) and projection microstereolithography (PµSL) rely on a range of polymeric materials1,2. However, it can be difficult to control the surface roughness and chemistry of the complex, micro-/nano-structured devices. We use Atomic Layer Deposition (ALD), a technique compatible with many different substrates, to coat different polymers, exploring its potential to improve micro-device operation stability. The ALD process is integrated with particle-in-cell (PIC) and finite volume based (FVM) computational fluid dynamics (CFD) to determine the boundary layer thickness and optimal ALD parameters. This allows us to determine the coating properties on complex 3D structures, such as Gas Dynamic Virtual Nozzles (GDVN), used for sample delivery at X-ray free electron lasers (XFEL) and synchrotrons. The ALD coating can reduce the surface roughness, improve temperature resistance, and modify the surface chemistry. In combination with 3D-microprinting and CFD modeling, ALD offers a versatile approach to fabricate advanced, reliable microdevices for X-ray applications. 1: Trebbin et al., Lab Chip 2014, 14, 1733-1745 2: Nelson et al., Opt.Exp 2016, 11, 11515-11530 |
Tuesday, April 16, 2019 3:54PM - 4:06PM |
Z13.00003: The dual nature of consciousness. Akruti Rambahor Mishra As de broglie hypothesized , All matter exhibits wave nature . Does Consciousness possess a wave nature too ? How does it behave as wave ? |
Tuesday, April 16, 2019 4:06PM - 4:18PM |
Z13.00004: Hypersurface Tension: A Mechanical Model of Spacetime with Gravitation and Quantum Geometry Howard A Perko It is well known that a three-dimensional volume is a three-surface in four-dimensions. Statistical thermodynamics and the bounding of quantum states at any stable surface gives rise to negative stress-energy (surface tension) regardless of the dimensionality of the hypersurface. A mechanical model of spacetime with hypersurface tension was introduced at a prior conference. In the prior work, similarities between spacetime geometry and equations of quantum mechanics, namely Klein-Gordon, Schrödinger, Heisenberg, and Weyl, were identified. In this talk, the model is extended to include further comparisons with general relativity. A symmetric nondegenerate anisotropic elastic tensor is proposed as a constitutive relation between stress energy and curvature instead of the traditional Einstein constant. It is shown that such a relation provides a spatial geometry resembling quantum mechanics while temporal terms and the overall structure of tensor equations remain consistent with general relativity. Current efforts to test and validate the model are described. |
Tuesday, April 16, 2019 4:18PM - 4:30PM |
Z13.00005: Formal Unification of Gravity and Particle Physics in Lagrangian Euclidean Space with Experimental Predictions Hontas Farmer Presenting an alternative to quantization of General Relativity then unification with the Standard Model. That basic program has consumed countless person years of brain power from the worlds brightest minds. Instead, we try relativization of the Standard Model of Particle Physics, write it in a form that is compatible with General Relativity. Then treat the Lagrangians of General Relativity, the Standard Model and a placeholder for dark matter as coordinates in a 3D space of Lagrangians. From this point standard mathematical tools of modern physics are used to make predictions. Predictions such as computing the limits of, and corrections due to, gravity or quantum effects. These are in areas as diverse as particle physics, gravitational wave physics, and dark matter searches. |
Tuesday, April 16, 2019 4:30PM - 4:42PM |
Z13.00006: Meta-nonlinearity and plasma effect to explain pulsed light transmissionthrough a subwavelength plasmonic metal slit Kuan-Ren Chen, Jian-Shiung Hong, Alex E. Chen The transmission of a light pulse through a subwavelength metal slit remains as a fundamental physics puzzle. We show that nonlinearity can be induced in this system even considering only linear materials and processes due to the roundtrip reflection within the cavity and the resultant superposition of the transmitted light sub-pulses. The superposition of sub-pulse lights with a fixed phase delay in between produces a periodic light that beats with its original light frequency and results the meta-nonlinearity that is new in additional to the well known nonlinearities from large amplitude, material nonlinearity, and two or more lights with different frequencies. Intriguing transient behavior, step phasor, non-smoothness, nonlinear phase shift(s), nonuniform dispersion, plasma, and sub-pulse spreading are key features. The wave function of the transmitted field is highly sensitive to the phase delay due to the roundtrip reflection within the slit; especially, at half or integer periods. Analytical models are proposed to understand and explain the underneath new physics. Modeling results agree well with simulations. The academic and industrial applications are broad. |
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