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Articles 1 - 11 of 11
Full-Text Articles in Physics
A Hybrid Achromatic Metalens, Fatih Balli, Mansoor A. Sultan, Sarah K. Lami, J. Todd Hastings
A Hybrid Achromatic Metalens, Fatih Balli, Mansoor A. Sultan, Sarah K. Lami, J. Todd Hastings
Electrical and Computer Engineering Faculty Publications
Metalenses, ultra-thin optical elements that focus light using subwavelength structures, have been the subject of a number of recent investigations. Compared to their refractive counterparts, metalenses offer reduced size and weight, and new functionality such as polarization control. However, metalenses that correct chromatic aberration also suffer from markedly reduced focusing efficiency. Here we introduce a Hybrid Achromatic Metalens (HAML) that overcomes this trade-off and offers improved focusing efficiency over a broad wavelength range from 1000-1800 nm. HAMLs can be designed by combining recursive ray-tracing and simulated phase libraries rather than computationally intensive global search algorithms. Moreover, HAMLs can be fabricated …
A Simple Method Of Coil Design, M. Rawlik, A. Eggenberger, J. Krempel, Christopher Crawford, K. Kirch, F. M. Piegsa, G. Quéméner
A Simple Method Of Coil Design, M. Rawlik, A. Eggenberger, J. Krempel, Christopher Crawford, K. Kirch, F. M. Piegsa, G. Quéméner
Physics and Astronomy Faculty Publications
In this article, we present a method to design a coil producing an arbitrarily shaped magnetic field by restricting the path of the coil's wires to a regular grid. The solution is then found by a simple least squares minimum. We discuss practical applications, in particular, in the active magnetic field stabilization system of the neutron electric dipole moment experiment at the Paul Scherrer Institute in Villigen, Switzerland. We also publish the software implementation of the method.
The 3d Stress-Tensor Bootstrap, Anatoly Dymarsky, Filip Kos, Petr Kravchuk, David Poland, David Simmons-Duffin
The 3d Stress-Tensor Bootstrap, Anatoly Dymarsky, Filip Kos, Petr Kravchuk, David Poland, David Simmons-Duffin
Physics and Astronomy Faculty Publications
We study the conformal bootstrap for 4-point functions of stress tensors in parity-preserving 3d CFTs. To set up the bootstrap equations, we analyze the constraints of conformal symmetry, permutation symmetry, and conservation on the stress-tensor 4-point function and identify a non-redundant set of crossing equations. Studying these equations numerically using semidefinite optimization, we compute bounds on the central charge as a function of the independent coefficient in the stress-tensor 3-point function. With no additional assumptions, these bounds numerically reproduce the conformal collider bounds and give a general lower bound on the central charge. We also study the effect of gaps …
Three Dimensional View Of Arbitrary Q Syk Models, Sumit R. Das, Aminik Ghosh, Antal Jevicki, Kenta Suzuki
Three Dimensional View Of Arbitrary Q Syk Models, Sumit R. Das, Aminik Ghosh, Antal Jevicki, Kenta Suzuki
Physics and Astronomy Faculty Publications
In [15] it was shown that the spectrum and bilocal propagator of SYK model with four fermion interactions can be realized as a three dimensional model in AdS2 ×S1/Z2 with nontrivial boundary conditions in the additional dimension. In this paper we show that a similar picture holds for generalizations of the SYK model with q-fermion interactions. The 3D realization is now given on a space whose metric is conformal to AdS2 × S1/Z2 and is subject to a non-trivial potential in addition to a delta function at the center of …
Universality Of Fast Quenches From The Conformal Perturbation Theory, Anatoly Dymarsky, Michael Smolkin
Universality Of Fast Quenches From The Conformal Perturbation Theory, Anatoly Dymarsky, Michael Smolkin
Physics and Astronomy Faculty Publications
We consider global quantum quenches, a protocol when a continuous field theoretic system in the ground state is driven by a homogeneous time-dependent external interaction. When the typical inverse time scale of the interaction is much larger than all relevant scales except for the UV-cutoff the system’s response exhibits universal scaling behavior. We provide both qualitative and quantitative explanations of this universality and argue that physics of the response during and shortly after the quench is governed by the conformal perturbation theory around the UV fixed point. We proceed to calculate the response of one and two-point correlation functions confirming …
Ionic Thermoelectric Paper, Fei Jiao, Ali Naderi, Dan Zhao, Joshua Schlueter, Maryam Shahi, Jonas Sundström, Hjalmar Granberg, Jesper Edberg, Ujwala Ail, Joseph W. Brill, Tom Lindström, Magnus Berggren, Xavier Crispin
Ionic Thermoelectric Paper, Fei Jiao, Ali Naderi, Dan Zhao, Joshua Schlueter, Maryam Shahi, Jonas Sundström, Hjalmar Granberg, Jesper Edberg, Ujwala Ail, Joseph W. Brill, Tom Lindström, Magnus Berggren, Xavier Crispin
Physics and Astronomy Faculty Publications
Ionic thermoelectric materials, for example, polyelectrolytes such as polystyrene sulfonate sodium (PSSNa), constitute a new class of materials which are attracting interest because of their large Seebeck coefficient and the possibility that they could be used in ionic thermoelectric SCs (ITESCs) and field effect transistors. However, pure polyelectrolyte membranes are not robust or flexible. In this paper, the preparation of ionic thermoelectric paper using a simple, scalable and cost-effective method is described. After a composite was fabricated with nanofibrillated cellulose (NFC), the resulting NFC–PSSNa paper is flexible and mechanically robust, which is desirable if it is to be used in …
Enhanced Metallic Properties Of Srruo3 Thin Films Via Kinetically Controlled Pulsed Laser Epitaxy, Justin K. Thompson, J. Nichols, S. Lee, S. Ryee, John H. Gruenewald, John G. Connell, Maryam Souri, J. M. Johnson, J. Hwang, M. J. Han, H. N. Lee, D. -W. Kim, Sung S. Ambrose Seo
Enhanced Metallic Properties Of Srruo3 Thin Films Via Kinetically Controlled Pulsed Laser Epitaxy, Justin K. Thompson, J. Nichols, S. Lee, S. Ryee, John H. Gruenewald, John G. Connell, Maryam Souri, J. M. Johnson, J. Hwang, M. J. Han, H. N. Lee, D. -W. Kim, Sung S. Ambrose Seo
Physics and Astronomy Faculty Publications
Metal electrodes are a universal element of all electronic devices. Conducting SrRuO3 (SRO) epitaxial thin films have been extensively used as electrodes in complex-oxide heterostructures due to good lattice mismatches with perovskite substrates. However, when compared to SRO single crystals, SRO thin films have shown reduced conductivity and Curie temperatures (TC), which can lead to higher Joule heating and energy loss in the devices. Here, we report that high-quality SRO thin films can be synthesized by controlling the plume dynamics and growth rate of pulsed laser epitaxy (PLE) with real-time optical spectroscopic monitoring. The SRO thin …
Hallmarks Of The Mott-Metal Crossover In The Hole-Doped Pseudospin-1/2 Mott Insulator Sr2Iro4, Yue Cao, Qiang Wang, Justin A. Waugh, Theodore J. Reber, Haoxiang Li, Xiaoqing Zhou, Stephen Parham, S. -R. Park, Nicholas C. Plumb, Eli Rotenberg, Aaron Bostwick, Jonathan D. Denlinger, Tongfei Qi, Michael A. Hermele, Gang Cao, Daniel S. Dessau
Hallmarks Of The Mott-Metal Crossover In The Hole-Doped Pseudospin-1/2 Mott Insulator Sr2Iro4, Yue Cao, Qiang Wang, Justin A. Waugh, Theodore J. Reber, Haoxiang Li, Xiaoqing Zhou, Stephen Parham, S. -R. Park, Nicholas C. Plumb, Eli Rotenberg, Aaron Bostwick, Jonathan D. Denlinger, Tongfei Qi, Michael A. Hermele, Gang Cao, Daniel S. Dessau
Physics and Astronomy Faculty Publications
The physics of doped Mott insulators remains controversial after decades of active research, hindered by the interplay among competing orders and fluctuations. It is thus highly desired to distinguish the intrinsic characters of the Mott-metal crossover from those of other origins. Here we investigate the evolution of electronic structure and dynamics of the hole-doped pseudospin-1/2 Mott insulator Sr2IrO4. The effective hole doping is achieved by replacing Ir with Rh atoms, with the chemical potential immediately jumping to or near the top of the lower Hubbard band. The doped iridates exhibit multiple iconic low-energy features previously observed …
An Organic Mixed Ion-Electron Conductor For Power Electronics, Abdellah Malti, Jesper Edberg, Hjalmar Granberg, Zia Ullah Khan, Jens W. Andreasen, Xianjie Liu, Dan Zhao, Hao Zhang, Yulong Yao, Joseph W. Brill, Isak Engquist, Mats Fahlman, Lars Wågberg, Xavier Crispin, Magnus Berggren
An Organic Mixed Ion-Electron Conductor For Power Electronics, Abdellah Malti, Jesper Edberg, Hjalmar Granberg, Zia Ullah Khan, Jens W. Andreasen, Xianjie Liu, Dan Zhao, Hao Zhang, Yulong Yao, Joseph W. Brill, Isak Engquist, Mats Fahlman, Lars Wågberg, Xavier Crispin, Magnus Berggren
Physics and Astronomy Faculty Publications
A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.
Ferromagnetic Resonance Study Of Eightfold Artificial Ferromagnetic Quasicrystals, Vinayak Shantaram Bhat, J. Sklenar, J. Woods, B. Farmer, J. B. Ketterson, Jeffrey Todd Hastings, Lance E. De Long
Ferromagnetic Resonance Study Of Eightfold Artificial Ferromagnetic Quasicrystals, Vinayak Shantaram Bhat, J. Sklenar, J. Woods, B. Farmer, J. B. Ketterson, Jeffrey Todd Hastings, Lance E. De Long
Physics and Astronomy Faculty Publications
We have performed broadband (10 MHz–18 GHz) and narrowband (9.7 GHz) ferromagnetic resonance (FMR) measurements on permalloy thin films patterned with quasiperiodic Ammann tilings having eightfold rotational symmetry. We observed highly reproducible mode structures in the low-frequency, hysteretic regime in which domain walls and unsaturated magnetization textures exist. A minimum of 10 robust modes were observed in patterned samples, compared to the single uniform mode observed in unpatterned permalloy films. The field dependence and approximate eightfold rotational symmetry of the FMR spectra are in good agreement with micromagnetic simulations that confirm the importance of patterning for controlling static and dynamic …
Controlled Magnetic Reversal In Permalloy Films Patterned Into Artificial Quasicrystals, Vinayak Shantaram Bhat, J. Sklenar, B. Farmer, J. Woods, Jeffrey Todd Hastings, S. J. Lee, J. B. Ketterson, Lance E. De Long
Controlled Magnetic Reversal In Permalloy Films Patterned Into Artificial Quasicrystals, Vinayak Shantaram Bhat, J. Sklenar, B. Farmer, J. Woods, Jeffrey Todd Hastings, S. J. Lee, J. B. Ketterson, Lance E. De Long
Physics and Astronomy Faculty Publications
We have patterned novel Permalloy thin films with quasicrystalline Penrose P2 tilings and measured their dc magnetization and ferromagnetic resonance absorption. Reproducible anomalies in the hysteretic, low-field data signal a series of abrupt transitions between ordered magnetization textures, culminating in a smooth evolution into a saturated state. Micromagnetic simulations compare well to experimental dc hysteresis loops and ferromagnetic resonance spectra and indicate that systematic control of magnetic reversal and domain wall motion can be achieved via tiling design, offering a new paradigm of magnonic quasicrystals.