Search results for "Theoretical Physics"
showing 10 items of 751 documents
Pac-Man Josephson junctions: Useful trigonometric puzzles?
2020
Abstract Rather interesting trigonometric equations arise when considering a Josephson junction obtained by embedding a Pac-Man shaped superconducting island in between two superconducting electrodes. In the present work we unfold these equations, written in terms of the superconducting phase difference between the two electrodes, and find the current-phase relation and the maximum superconducting current of the Josephson junction network. The solution of the trigonometric equations defining the superconducting current state of the system can be proposed to advanced high-school students or to undergraduate students in an interdisciplinary lecture.
Comment on “Nonlocal In-Plane Resistance due to Vortex-Antivortex Dynamics in High-TcSuperconducting Films”
1999
A Comment on the Letter by Y. Kopelevich et al., Phys. Rev. Lett. 80, 4048 (1998). The authors of the Letter offer a Reply.
Skyrmion formation due to unconventional magnetic modes in anisotropic multiband superconductors
2018
Multiband superconductors have a sufficient number of degrees of freedom to allow topological excitations characterized by Skyrmionic topological invariants. In the most common, clean s-wave multiband, systems the interband magnetic coupling favours composite vortex solutions, without a Skyrmionic topological charge. It was discussed recently that certain kinds of anisotropies lead to hybridisation of the interband phase difference (Leggett) mode with magnetic modes, dramatically changing the hydromagnetostatics of the system. Here we report this effect for a range of parameters that substantially alter the nature of the topological excitations, leading to solutions characterized by a nontr…
Arithmetic and geometry of a K3 surface emerging from virtual corrections to Drell–Yan scattering
2020
We study a K3 surface, which appears in the two-loop mixed electroweak-quantum chromodynamic virtual corrections to Drell--Yan scattering. A detailed analysis of the geometric Picard lattice is presented, computing its rank and discriminant in two independent ways: first using explicit divisors on the surface and then using an explicit elliptic fibration. We also study in detail the elliptic fibrations of the surface and use them to provide an explicit Shioda--Inose structure. Moreover, we point out the physical relevance of our results.
Design and synthesis of the first triply twisted Möbius annulene.
2014
As long as 50 years ago theoretical calculations predicted that Mobius annulenes with only one π surface and one edge would exhibit peculiar electronic properties and violate the Huckel rules. Numerous synthetic attempts notwithstanding, the first singly twisted Mobius annulene was not prepared until 2003. Here we present a general, rational strategy to synthesize triply or even more highly twisted cyclic π systems. We apply this strategy to the preparation of a triply twisted [24]dehydroannulene, the structure of which was confirmed by X-ray analysis. Our strategy is based on the topological transformation of 'twist' into 'writhe'. The advantage is twofold: the product exhibits a lower deg…
Thermodynamics of Nanoparticles: Experimental Protocol Based on a Comprehensive Ginzburg-Landau Interpretation
2014
MATERIAUX+SMR:SDA; The effects of surface and interface on the thermodynamics of small particles require a deeper understanding. This step is crucial for the development of models that can be used for decision-making support to design nanomaterials with original properties. On the basis of experimental results for phase transitions in compressed ZnO nanoparticles, we show the limitations of classical thermodynamics approaches (Gibbs and Landau). We develop a new model based on the Ginzburg-Landau theory that requires the consideration of several terms, such as the interaction between nanoparticles, pressure gradients, defect density, and so on. This phenomenological approach sheds light on …
Enabling quantum non-Markovian dynamics by injection of classical colored noise
2017
The non-Markovian nature of quantum systems recently turned to be a key subject for investigations on open quantum system dynamics. Many studies, from its theoretical grounding to its usefulness as a resource for quantum information processing and experimental demonstrations, have been reported in the literature. Typically, in these studies, a structured reservoir is required to make non-Markovian dynamics emerge. Here, we investigate the dynamics of a qubit interacting with a bosonic bath and under the injection of a classical stochastic colored noise. A canonical Lindblad-like master equation for the system is derived by using the stochastic wave function formalism. Then, the non-Markovia…
LA FÍSICA TEÓRICA BAJO EL FOCO DE LO FANTÁSTICO: UNA REFLEXIÓN SOBRE LO REAL Y SUS FRACTURAS EN EL DISCURSO CIENTÍFICO
2018
Quite often fantastic literature has been studied using ideas from theoretical physics in order to verify how the development of the latter modifies the reader's perception of the former. Instead, this article proposes the opposite: this article will explore theoretical physics using the ideas from the fantastic. The core principle here is that both reflect on the reality and fracture it, changing the reader's reality paradigm. While physics changes it from reality, using to it the principles of the mathematics, the fantastic does this using (and fracturing) a fictional space.
Analysis of spectral line shapes in low-temperature plasma by means of inverse ill-posed problem solution
2017
Promocijas darbs ir veltīts zemtemperatūras plazmas diagnostikas metodes attīstīšanai, augstfrekvences bezelektrodu lampām (ABL). Darbā tika izstrādāta jauna metode spektroskopisko datu apstrādei un reālo spektrāllīniju kontūru noteikšanai, risinot nekorekto apgriezto uzdevumu, kas balstās uz Tihonova regularizācijas algoritmu. Metode tika testēta aprēķinot patiesās profilu formas izmantojot eksperimentāli iegūtas Hg līnijās, emitētas no specialas formas mikro ABL. Tika pierādīts, ka aparatūras funkcijas neņemšana vērā zemtemperatūras plazmas gadījumā var ieviest lielu neprecizitāti, nosakot profilu formu un platumu un, sekojoši, ABL temperatūru. Tika analizēta arī atkarība no bufergāzes ve…
On essential spectra of operator-matrices and their Feshbach maps
2004
Abstract A connection between the essential spectrum of certain operator-matrices and essential spectra of the corresponding “Feshbach maps” is discussed and applied to some concrete rational operator-valued functions.