scholarly journals Rephasing Invariant for Three-Neutrino Oscillations Governed by a Non-Hermitian Hamiltonian

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1285
Author(s):  
Dmitry V. Naumov ◽  
Vadim A. Naumov ◽  
Dmitry S. Shkirmanov
Keyword(s):  
Time Reversal ◽  
Quantum Dynamics ◽  
Neutrino Oscillations ◽  
Time Reversal Symmetry ◽  
Direct Connection ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Dirac Neutrino ◽  
Absorbing Media ◽  
Neutrino Propagation

Time-reversal symmetry is broken for mixed and possibly unstable Dirac neutrino propagation through absorbing media. This implies that interplay between the neutrino mixing, refraction, absorption and/or decay can be described by non-Hermitian quantum dynamics. We derive an identity which sets up direct connection between the fundamental neutrino parameters (mixing angles, CP-violating phase, mass-squared splittings) in vacuum and their effective counterparts in matter.

scholarly journals NEUTRINO OSCILLATIONS AND THE EXACT PARITY MODEL

1994 ◽  
Vol 09 (02) ◽  
pp. 169-179 ◽  
Author(s):  
R. FOOT
Keyword(s):  
Neutrino Mass ◽  
General Result ◽  
Neutrino Oscillations ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Solar Neutrinos ◽  
Specific Model ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Significant Deficit

We re-examine neutrino oscillations in exact parity models. Previously it was shown in a specific model that large neutrino mixing angles result. We show here that this is a general result of neutrino mixing in exact parity models provided that the neutrino mass matrix is real. In this case, the effects of neutrino mixing in exact parity models is such that the probability of a given weak eigenstate remaining in that eigenstate averages to less than half when averaged over many oscillations. This result is interesting in view of the accumulating evidence for a significant deficit in the number of solar neutrinos. It may also be of relevance to the atmospheric neutrino anomaly.

scholarly journals ONE-PION EVENTS BY ATMOSPHERIC NEUTRINOS: A THREE-FLAVOR ANALYSIS

2001 ◽  
Vol 16 (08) ◽  
pp. 1417-1429 ◽  
Author(s):  
K. R. S. BALAJI ◽  
G. RAJASEKARAN ◽  
S. UMA SANKAR
Keyword(s):  
Diagnostic Method ◽  
Neutrino Oscillations ◽  
Neutral Current ◽  
Charged Current ◽  
Atmospheric Neutrinos ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Flavor Oscillations ◽  
Flavor Analysis ◽  
The One

We study the one-pion events produced via neutral current (NC) and charged current (CC) interactions by the atmospheric neutrinos. We analyze the ratios of CC events to the NC events in the framework of neutrino oscillations. These ratios can distinguish between different combinations of neutrino mixing angles in the case of three-flavor oscillations. They also provide a good diagnostic method to distinguish νμ→ντ oscillations from νμ→νs oscillations.

scholarly journals CAN THE SUPER-KAMIOKANDE ATMOSPHERIC DATA PREDICT THE SOLAR NEUTRINO DEFICIT?

1999 ◽  
Vol 14 (10n11) ◽  
pp. 689-700 ◽  
Author(s):  
ION STANCU
Keyword(s):  
Solar Neutrino ◽  
Neutrino Oscillations ◽  
Atmospheric Neutrino ◽  
Neutrino Flux ◽  
Experimental Results ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Atmospheric Data ◽  
Mixing Matrix ◽  
Good Agreement

In this letter we show that the evidence for neutrino oscillations from the super-Kamiokande atmospheric neutrino data fully determines the 3×3 neutrino-oscillations mixing matrix and predicts an energy-independent solar neutrino deficit at the level of 45%. This corresponds to a ratio of measured to predicted neutrino flux of [Formula: see text], in good agreement with the experimental results. We achieve this result within the framework of a minimal, three-generation neutrino mixing, with mass squared differences of ΔM2≃0.45 eV 2 and [Formula: see text]. The mixing matrix derived here is characterized by the mixing angles θ=35.1°, β=5.5° and ψ=23.3°, and a vanishing CP-violating phase, δ=0.

scholarly journals Time-Reversal Symmetry and Arrow of Time in Quantum Mechanics of Open Systems

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 380 ◽  
Author(s):  
Naomichi Hatano ◽  
Gonzalo Ordonez
Keyword(s):  
Time Reversal ◽  
Quantum Dynamics ◽  
Open Systems ◽  
Open Quantum Systems ◽  
Functional Space ◽  
Time Reversal Symmetry ◽  
Arrow Of Time ◽  
Initial State ◽  
Resonant States ◽  
Complex Eigenvalues

It is one of the most important and long-standing issues of physics to derive the irreversibility out of a time-reversal symmetric equation of motion. The present paper considers the breaking of the time-reversal symmetry in open quantum systems and the emergence of an arrow of time. We claim that the time-reversal symmetric Schrödinger equation can have eigenstates that break the time-reversal symmetry if the system is open in the sense that it has at least a countably infinite number of states. Such eigenstates, namely the resonant and anti-resonant states, have complex eigenvalues. We show that, although these states are often called “unphysical”, they observe the probability conservation in a particular way. We also comment that the seemingly Hermitian Hamiltonian is non-Hermitian in the functional space of the resonant and anti-resonant states, and hence there is no contradiction in the fact that it has complex eigenvalues. We finally show how the existence of the states that break the time-reversal symmetry affects the quantum dynamics. The dynamics that starts from a time-reversal symmetric initial state is dominated by the resonant states for t > 0 ; this explains the phenomenon of the arrow of time, in which the decay excels the growth. The time-reversal symmetry holds in that the dynamic ending at a time-reversal symmetric final state is dominated by the anti-resonant states for t < 0 .

scholarly journals GEOMETRIC MEAN NEUTRINO MASS RELATION

2007 ◽  
Vol 22 (25n28) ◽  
pp. 2107-2112 ◽  
Author(s):  
XIAO-GANG HE ◽  
A. ZEE
Keyword(s):  
Neutrino Oscillations ◽  
Geometric Mean ◽  
Neutrino Masses ◽  
Mass Relation ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Central Values ◽  
Cosmological Observation ◽  
The Absolute ◽  
Using Data

Present experimental data from neutrino oscillations have provided much information about the neutrino mixing angles. Since neutrino oscillations only determine the mass squared differences [Formula: see text], the absolute values for neutrino masses mi, can not be determined using data just from oscillations. In this work we study implications on neutrino masses from a geometric mean mass relation [Formula: see text] which enables one to determined the absolute masses of the neutrinos. We find that the central values of the three neutrino masses and their 2σ errors to be m1 = (1.58 ± 0.18) meV , m2 = (9.04 ± 0.42) meV , and m3 = (51.8 ± 3.5) meV . Implications for cosmological observation, beta decay and neutrinoless double beta decays are discussed.

scholarly journals Odd Willis coupling induced by broken time-reversal symmetry

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Li Quan ◽  
Simon Yves ◽  
Yugui Peng ◽  
Hussein Esfahlani ◽  
Andrea Alù
Keyword(s):  
Time Reversal ◽  
Time Reversal Symmetry ◽  
Acoustic Metamaterials ◽  
Asymmetric Structures ◽  
Sound Control ◽  
Wavefront Shaping ◽  
Scattering Response ◽  
Symmetric Structures ◽  
Signal Routing ◽  
Broad Interest

AbstractWhen sound interacts with geometrically asymmetric structures, it experiences coupling between pressure and particle velocity, known as Willis coupling. While in most instances this phenomenon is perturbative in nature, tailored asymmetries combined with resonances can largely enhance it, enabling exotic acoustic phenomena. In these systems, Willis coupling obeys reciprocity, imposing an even symmetry of the Willis coefficients with respect to time reversal and the impinging wave vector, which translates into stringent constraints on the overall scattering response. In this work, we introduce and experimentally observe a dual form of acoustic Willis coupling, arising in geometrically symmetric structures when time-reversal symmetry is broken, for which the pressure-velocity coupling is purely odd-symmetric. We derive the conditions to maximize this effect, we experimentally verify it in a symmetric subwavelength scatterer biased by angular momentum, and we demonstrate the opportunities for sound scattering enabled by odd Willis coupling. Our study opens directions for acoustic metamaterials, with direct implications for sound control, non-reciprocal scattering, wavefront shaping and signal routing, of broad interest also for nano-optics, photonics, elasto-dynamics, and mechanics.

scholarly journals Symmetry aspects in the macroscopic dynamics of magnetorheological gels and general liquid crystalline magnetic elastomers

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Harald Pleiner ◽  
Helmut R. Brand
Keyword(s):  
Electric Fields ◽  
Time Reversal ◽  
Liquid Crystalline ◽  
Second Law Of Thermodynamics ◽  
Time Reversal Symmetry ◽  
Local Conservation ◽  
Continuous Symmetry ◽  
Polar Order ◽  
Preferred Direction ◽  
Symmetry Properties

Abstract We investigate theoretically the macroscopic dynamics of various types of ordered magnetic fluid, gel, and elastomeric phases. We take a symmetry point of view and emphasize its importance for a macroscopic description. The interactions and couplings among the relevant variables are based on their individual symmetry behavior, irrespective of the detailed nature of the microscopic interactions involved. Concerning the variables we discriminate between conserved variables related to a local conservation law, symmetry variables describing a (spontaneously) broken continuous symmetry (e.g., due to a preferred direction) and slowly relaxing ones that arise from special conditions of the system are considered. Among the relevant symmetries, we consider the behavior under spatial rotations (e.g., discriminating scalars, vectors or tensors), under spatial inversion (discriminating e.g., polar and axial vectors), and under time reversal symmetry (discriminating e.g., velocities from polarizations, or electric fields from magnetic ones). Those symmetries are crucial not only to find the possible cross-couplings correctly but also to get a description of the macroscopic dynamics that is compatible with thermodynamics. In particular, time reversal symmetry is decisive to get the second law of thermodynamics right. We discuss (conventional quadrupolar) nematic order, polar order, active polar order, as well as ferromagnetic order and tetrahedral (octupolar) order. In a second step, we show some of the consequences of the symmetry properties for the various systems that we have worked on within the SPP1681, including magnetic nematic (and cholesteric) elastomers, ferromagnetic nematics (also with tetrahedral order), ferromagnetic elastomers with tetrahedral order, gels and elastomers with polar or active polar order, and finally magnetorheological fluids and gels in a one- and two-fluid description.

scholarly journals Unsplit superconducting and time reversal symmetry breaking transitions in Sr2RuO4 under hydrostatic pressure and disorder

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Vadim Grinenko ◽  
Debarchan Das ◽  
Ritu Gupta ◽  
Bastian Zinkl ◽  
Naoki Kikugawa ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Symmetry Breaking ◽  
Time Reversal ◽  
Order Parameter ◽  
Muon Spin Rotation ◽  
Horizontal Line ◽  
Time Reversal Symmetry ◽  
Zero Field ◽  
Symmetry Protected ◽  
Line Node

AbstractThere is considerable evidence that the superconducting state of Sr2RuO4 breaks time reversal symmetry. In the experiments showing time reversal symmetry breaking, its onset temperature, TTRSB, is generally found to match the critical temperature, Tc, within resolution. In combination with evidence for even parity, this result has led to consideration of a dxz ± idyz order parameter. The degeneracy of the two components of this order parameter is protected by symmetry, yielding TTRSB = Tc, but it has a hard-to-explain horizontal line node at kz = 0. Therefore, s ± id and d ± ig order parameters are also under consideration. These avoid the horizontal line node, but require tuning to obtain TTRSB ≈ Tc. To obtain evidence distinguishing these two possible scenarios (of symmetry-protected versus accidental degeneracy), we employ zero-field muon spin rotation/relaxation to study pure Sr2RuO4 under hydrostatic pressure, and Sr1.98La0.02RuO4 at zero pressure. Both hydrostatic pressure and La substitution alter Tc without lifting the tetragonal lattice symmetry, so if the degeneracy is symmetry-protected, TTRSB should track changes in Tc, while if it is accidental, these transition temperatures should generally separate. We observe TTRSB to track Tc, supporting the hypothesis of dxz ± idyz order.

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