Optical Reciprocity Induced Symmetry of the Scattering Eigenstates in Non-PT\cal PT-Symmetric Heterostructures

The scattering matrix $S$ obeys the unitary relation $S^\dagger S=1$ in a Hermitian system and the symmetry property ${\cal PT}S{\cal PT}=S^{-1}$ in a Parity-Time (${\cal PT}$) symmetric system. Here we report a different symmetry relation of the $S$ matrix in a one-dimensional heterostructure, which is given by the amplitude ratio of the incident waves in the scattering eigenstates. It originates from the optical reciprocity and holds independent of the Hermiticity or $\cal PT$ symmetry of the system. Using this symmetry relation, we probe a quasi-transition that is reminiscent of the spontaneous symmetry breaking of a $\cal PT$-symmetric $S$ matrix, now with unbalanced gain and loss and even in the absence of gain. We show that the additional symmetry relation provides a clear evidence of an exceptional point, even when all other signatures of the $\cal PT$ symmetry breaking are completely erased. We also discuss the existence of a final exceptional point in this correspondence, which is attributed to asymmetric reflections from the two sides of the heterostructure.Comment: 5 pages, 4 figure

Half-life Expectations for Neutrinoless Double Beta Decay in Standard and Non-Standard Scenarios

We investigate the half-life expectations for neutrinoless double beta decay by applying statistical distributions of neutrino mixing observables, neutrino mass constraints from cosmology and nuclear matrix elements. The analysis is performed in the standard scenario of active Majorana neutrino exchange, when light sterile neutrinos are added, and within TeV-scale left-right symmetric frameworks. The latter two cases correspond to a modified phenomenology of double beta decay for a normal and inverted mass ordering, and thus different discovery potential for future experiments.Comment: 18 pages, 10 figures, and 4 table

A Novel Approach to Study Atmospheric Neutrino Oscillation

We develop a general theoretical framework to analytically disentangle the contributions of the neutrino mass hierarchy, the atmospheric mixing angle, and the CP phase, in neutrino oscillations. To illustrate the usefulness of this framework, especially that it can serve as a complementary tool to neutrino oscillogram in the study of atmospheric neutrino oscillations, we take PINGU as an example and compute muon- and electron-like event rates with event cuts on neutrino energy and zenith angle. Under the assumption of exact momentum measurements of neutrinos with a perfect e-$\mu$ identification and no backgrounds, we find that the PINGU experiment has the potential of resolving the neutrino mass hierarchy and the octant degeneracies within 1-year run, while the measurement of the CP phase is significantly more challenging. Our observation merits a serious study of the detector capability of estimating the neutrino momentum for both muon- and electron-like events.Comment: 29 pages, 12 figures, reference updated, structure adjusted and text further improve

UVA Assisted 4-Thiothymidine for Cancer Treatment

This article reviews the developments of 4-thiothymidine analogues, assisted with UVA light, as a novel cancer therapy. First, the key points on synthetic chemistry, photochemistry and cellular toxicity of 4-thiothymidine are summarized. As the chemical structure of 4-thiothymidine is very similar to that of its parent thymidine, thus 4-thiothymidine can be readily incorporated into cellular DNA, and with the help of thymidine kinase, much more preferably into cancerous DNA. Unlike thymidine, 4-thiothymdine can absorb strongly in UVA (longer wavelengths of UV) light. Thus UVA-assisted 4-thiothymidine offers an effective cancer treatment. Some underlying mechanisms of action by 4-thiothymidine/UVA and compares this cancer approach with the commonly used photodynamic therapy are discussed. The various interactions between 4-thiothymidine with human serum albumin are introduced. Finally, a short conclusion on the past efforts and a brief prospect for future work in this exciting research field are given