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One of the commonly used approaches to capture dependence in multivariate survival data is through the frailty variables. The identifiability issues should be carefully investigated while modeling multivariate survival with or without competing risks. The use of non-parametric frailty distribution(s) is sometimes preferred for its robustness and flexibility properties. In this paper, we consider modeling of bivariate survival data with competing risks through four different kinds of non-parametric frailty and parametric baseline cause-specific hazard functions to investigate the corresponding model identifiability. We make the common assumption of the frailty mean being equal to unity.

In survival analysis, frailty variables are often used to model the association in multivariate survival data. Identifiability is an important issue while working with such multivariate survival data with or without competing risks. In this work, we consider bivariate survival data with competing risks and investigate identifiability results with non-parametric baseline cause-specific hazards and different types of Gamma frailty. Prior to that, we prove that, when both baseline cause-specific hazards and frailty distributions are non-parametric, the model is not identifiable. We also construct a non-identifiable model when baseline cause-specific hazards are non-parametric but frailty distribution may be parametric. Thereafter, we consider four different Gamma frailty distributions, and the corresponding models are shown to be identifiable under fairly general assumptions.

Shared and correlated Gamma frailty models are widely used in the literature to model the association in multivariate current status data. In this paper, we have proposed two other new Gamma frailty models, namely shared cause-specific and correlated cause-specific Gamma frailty to capture association in bivariate current status data with competing risks. We have investigated the identifiability of the bivariate models with competing risks for each of the four frailty variables. We have considered maximum likelihood estimation of the model parameters. Thorough simulation studies have been performed to study the finite sample behaviour of the estimated parameters. Also, we have analyzed a real data set on hearing loss in two ears using Exponential type and Weibull type cause-specific baseline hazard functions with the four different Gamma frailty variables and compare the fits using AIC.

We study the Rees valuations and rational powers of several classes of invariant ideals, providing explicit descriptions in terms of certain polyhedra. This allows us to show that a version of Musta\c{t}\u{a}-Takagi's summation formula for rational powers holds for these ideals. Moreover, for arbitrary ideals over the complex numbers, we prove a weaker version of this formula that holds for high enough rational numbers. Our methods lead to a definition of rational powers of ideal sheaves in normal complex varieties inspired by work of Lejeune-Jalabert-Teissier and Lazarsfeld.

The telecloning protocol distributes quantum states from a single sender to multiple receivers via a shared entangled state by exploiting the notions of teleportation and approximate cloning. We investigate the optimal telecloning fidelities obtained using both Gaussian and non-Gaussian shared resources. When the shared non-Gaussian state is created by subtracting photons from both the modes of the Gaussian two-mode squeezed vacuum state, we demonstrate that higher telecloning fidelities can be achieved in comparison with its Gaussian counterpart. To quantify this advantage, we introduce a quadrature-based nonclassicality measure, which is capable of estimating the fidelity of the clones, both with Gaussian and non-Gaussian resource states. We further provide a linear optical setup for asymmetric telecloning of continuous variable states using a multimode entangled state., Comment: v1: 14 pages, 7 figures v2: close to published version

The mass-induced neutrino oscillation is a well established phenomenon that is based on the unitary mixing among three light active neutrinos. Remarkable precision on neutrino mixing parameters over the last decade or so has opened up the prospects for testing the possible non-unitarity of the standard 3$\nu$ mixing matrix, which may arise in the seesaw extensions of the Standard Model due to the admixture of three light active neutrinos with heavy isosinglet neutrinos. Because of this non-unitary neutrino mixing (NUNM), the oscillation probabilities among the three active neutrinos would be altered as compared to the probabilities obtained assuming a unitary 3$\nu$ mixing matrix. In such a NUNM scenario, neutrinos can experience an additional matter effect due to the neutral current interactions with the ambient neutrons. Atmospheric neutrinos having access to a wide range of energies and baselines can experience a significant modifications in Earth's matter effect due to NUNM. In this paper, for the first time, we study in detail how the NUNM parameter $\alpha_{32}$ affects the muon neutrino and antineutrino survival probabilities in a different way. Then, we place stringent constraints on $\alpha_{32}$ in a model independent fashion using the proposed 50 kt magnetized Iron Calorimeter (ICAL) detector under the India-based Neutrino Observatory (INO) project, which can efficiently detect the atmospheric $\nu_\mu$ and $\bar\nu_\mu$ separately in the multi-GeV energy range. Further, we discuss the advantage of charge identification capability of ICAL and the impact of uncertainties in oscillation parameters while constraining $\alpha_{32}$. We also compare the $\alpha_{32}$ sensitivity of ICAL with that of future long-baseline experiments DUNE and Hyper-K in isolation and combination., Comment: 39 pages, 8 figures, 5 tables, 2 appendices. Comments are welcome

A viable approach towards Quantum Gravity is the Doubly Special Relativity (DSR) framework in which an observer-independent finite energy upper bound (or a finite smallest length scale) appears quite naturally. In this work, we have studied the thermodynamic properties of an ideal gas in a specific DSR framework, known as the Magueijo-Smolin (MS) Model. We use the fact that DSR can be considered as nonlinear representation of Lorentz Group. Subsequently, various thermodynamic parameters of ideal gas have been derived in this modified framework to compare the corresponding deviations from the usual scenario due to the presence of the invariant energy (length) scale., Comment: 11 pages, 3 figures, submitted to journal for consideration

The discovery of new, flavor-dependent neutrino interactions would provide compelling evidence of physics beyond the Standard Model. We focus on interactions generated by the anomaly-free, gauged, abelian lepton-number symmetries, specifically $L_e-L_\mu$, $L_e-L_\tau$, and $L_\mu-L_\tau$, that introduce a new matter potential sourced by electrons and neutrons, potentially impacting neutrino flavor oscillations. We revisit, revamp, and improve the constraints on these interactions that can be placed via the flavor composition of the diffuse flux of high-energy astrophysical neutrinos, with TeV-PeV energies, i.e., the proportion of $\nu_e$, $\nu_\mu$, and $\nu_\tau$ in the flux. Because we consider mediators of these new interactions to be ultra-light, lighter than $10^{-10}$ eV, the interaction range is ultra-long, from km to Gpc, allowing vast numbers of electrons and neutrons in celestial bodies and the cosmological matter distribution to contribute to this new potential. We leverage the present-day and future sensitivity of high-energy neutrino telescopes and of oscillation experiments to estimate the constraints that could be placed on the coupling strength of these interactions. We find that, already today, the IceCube neutrino telescope demonstrates potential to constrain flavor-dependent long-range interactions significantly better than existing constraints, motivating further analysis. We also estimate the improvement in the sensitivity due to the next-generation neutrino telescopes such as IceCube-Gen2, Baikal-GVD, KM3NeT, P-ONE, and TAMBO., Comment: 46 pages, 17 figures, 2 tables, 6 appendices. Indirect limit from test of the equivalence principle removed from figures 1, 8, D3, and E5 and necessary changes made in the figure captions. Four new references 41, 63, 64, and 67 added. This version has the same content as the published article in JHEP

Unified theories such as string theory and loop quantum gravity allow the Lorentz Invariance Violation (LIV) at the Planck Scale ($M_P \sim 10^{19}$ GeV). Using an effective field theory, this effect can be observed at low energies in terms of new interactions with a strength of $\sim 1/M_P$. These new interactions contain operators with LIV coefficients which can be CPT-violating or CPT-conserving. In this work, we study in detail how these LIV parameters modify the transition probabilities in the next-generation long-baseline experiments, DUNE and T2HK. We evaluate the sensitivities of these experiments in isolation and combination to constrain the off-diagonal CPT-violating ($a_{e\mu}$, $a_{e\tau}$, $a_{\mu\tau}$) and CPT-conserving ($c_{e\mu}$, $c_{e\tau}$, $c_{\mu\tau}$) LIV parameters. We derive approximate compact analytical expressions of $\nu_{\mu}\to\nu_e$ and $\nu_{\mu}\to\nu_\mu$ probabilities in the presence of these LIV parameters to explain our numerical results. We explore the possible correlations and degeneracies between these LIV parameters & 3$\nu$ parameters $\theta_{23}$ & $\delta_{\rm CP}$. We find that for non-maximal values of $\theta_{23}$, there exist degenerate solutions in its opposite octant for standalone DUNE and T2HK. These degeneracies disappear when we combine the data from DUNE and T2HK. In case of no-show, we place the expected bounds on these CPT-violating and CPT-conserving LIV parameters at 95% C.L. using the standalone DUNE, T2HK, and their combination. We observe that due to its access to a longer baseline and high-energy neutrinos, DUNE has a better reach in probing all these LIV parameters as compared to T2HK. Since the terms containing the CPT-conserving LIV parameters are proportional to neutrino energy in oscillation probabilities, T2HK is almost insensitive to the CPT-conserving LIV parameters because it mostly deals with sub-GeV neutrinos., Comment: 40 pages, 13 figures, 7 tables, two appendices. T2HK replaced by Hyper-K in the entire paper, Table 2 slightly modified, two new tables added in section 4, a new appendix added containing three new figures, and more discussions added in the text. This version has the same contents as the published article in Journal of High Energy Physics

Hydrated proteins undergo a transition in the deeply supercooled regime, which is attributed to rapid changes in hydration water and protein structural dynamics. Here, we investigate the nanoscale stress relaxation in hydrated lysozyme proteins stimulated and probed by X-ray Photon Correlation Spectroscopy (XPCS). This approach allows us to access the nanoscale dynamic response in the deeply supercooled regime (T = 180 K) which is typically not accessible through equilibrium methods. The relaxation time constants exhibit Arrhenius temperature dependence upon cooling with a minimum in the Kohlrausch-Williams-Watts exponent at T = 227 K. The observed minimum is attributed to an increase in dynamical heterogeneity, which coincides with enhanced fluctuations observed in the two-time correlation functions and a maximum in the dynamic susceptibility quantified by the normalised variance $\chi_T$. Our study provides new insights into X-ray stimulated stress relaxation and the underlying mechanisms behind spatio-temporal fluctuations in biological granular materials.

After the landmark discovery of non-zero $\theta_{13}$ by the modern reactor experiments, unprecedented precision on neutrino mass-mixing parameters has been achieved over the past decade. This has set the stage for the discovery of leptonic CP violation (LCPV) at high confidence level in the next-generation long-baseline neutrino oscillation experiments. In this work, we explore in detail the possible complementarity among the on-axis DUNE and off-axis T2HK experiments to enhance the sensitivity to LCPV suppressing the $\theta_{23}-\delta_{\mathrm{CP}}$ degeneracy. We find that none of these experiments individually can achieve the milestone of 3$\sigma$ LCPV for at least 75% choices of $\delta_{\mathrm{CP}}$ in its entire range of $[-180^{\circ} , 180^{\circ}]$, with their nominal exposures and systematic uncertainties. However, their combination can attain the same for all values of $\theta_{23}$ with only half of their nominal exposures. We observe that the proposed T2HKK setup in combination with DUNE can further increase the CP coverage to more than 80% with only half of their nominal exposures. We study in detail how the coverage in $\delta_{\mathrm{CP}}$ for $\ge$ 3$\sigma$ LCPV depends on the choice of $\theta_{23}$, exposure, optimal runtime in neutrino and antineutrino modes, and systematic uncertainties in these experiments in isolation and combination. We find that with an improved systematic uncertainty of 2.7% in appearance mode, the standalone T2HK setup can provide a CP coverage of around 75% for all values of $\theta_{23}$. We also discuss the pivotal role of intrinsic, extrinsic, and total CP asymmetries in the appearance channel and extrinsic CP asymmetries in the disappearance channel while analyzing our results., Comment: 32 pages, 11 figures, 4 tables, and one appendix. A new section 5 added with a new figure 10, a new appendix added with a new figure 11, and more discussions added in the text. This version has the same content as the published article in The European Physical Journal C

In this paper, we work with certain families of ideals called $p$-families in rings of prime characteristic. This family of ideals is present in the theories of tight closure, Hilbert-Kunz multiplicity, and $F$-signature. For each $p$-family of ideals, we attach a Euclidean object called $p$-body, which is analogous to the Newton Okounkov body associated with a graded family of ideals. Using the combinatorial properties of $p$-bodies and algebraic properties of the Hilbert-Kunz multiplicity, we establish in this paper a Volume = Multiplicity formula for $p$-families of $\mathfrak{m}_{R}$-primary ideals in a Noetherian local ring $R$., Comment: 13 pages. arXiv admin note: text overlap with arXiv:1701.02575 by other authors

The task of a telecloning protocol is to send an arbitrary qubit possessed by a sender to multiple receivers. Instead of performing Bell measurement at the sender's node, if one applies unsharp measurement, we show that the shared state can be recycled for further telecloning protocol. Specifically, in case of a single sender and two receivers, the maximal attempting number, which is defined as the maximum number of rounds used by the channel to obtain quantum advantage in the fidelity, turns out to be three both for optimal and nonoptimal shared states for telecloning while the maximal number reduces to two in case of three receivers. Although the original telecloning with quantum advantage being possible for arbitrary numbers of receivers, we report that the recycling of resources is not possible in telecloning involving a single sender and more than three receivers, thereby demonstrating a no-go theorem. We also connect the maximal achievable fidelities in each round with the bipartite entanglement content of the reduced state between the sender and one of the receivers as well as with the monogamy score of entanglement., Comment: v1: 12 pages, 5 figures; v2: 13 pages, 5 figures; close to the publish version

In this paper we have considered an interacting model of dark energy and have looked into the evolution of the dark sectors. By solving the perturbation equations numerically, we have studied the imprints on the growth of matter as well as dark energy fluctuations. It has been found that for higher rate of interaction strength for the coupling term, visible imprints on the dark energy density fluctuations are observed at the early epochs of evolution., Comment: 10 pages, 5 figures. arXiv admin note: text overlap with arXiv:2110.02666

Astrophysical neutrinos are excellent probes of astroparticle physics and high-energy physics. With energies far beyond solar, supernovae, atmospheric, and accelerator neutrinos, high-energy and ultra-high-energy neutrinos probe fundamental physics from the TeV scale to the EeV scale and beyond. They are sensitive to physics both within and beyond the Standard Model through their production mechanisms and in their propagation over cosmological distances. They carry unique information about their extreme non-thermal sources by giving insight into regions that are opaque to electromagnetic radiation. This white paper describes the opportunities astrophysical neutrino observations offer for astrophysics and high-energy physics, today and in coming years., Comment: Contribution to Snowmass 2021, updated to include community feedback

X-ray free-electron lasers (XFELs) with megahertz repetition rate can provide novel insights into structural dynamics of biological macromolecule solutions. However, very high dose rates can lead to beam-induced dynamics and structural changes due to radiation damage. Here, we probe the dynamics of dense antibody protein (Ig-PEG) solutions using megahertz X-ray photon correlation spectroscopy (MHz-XPCS) at the European XFEL. By varying the total dose and dose rate, we identify a regime for measuring the motion of proteins in their first coordination shell, quantify XFEL-induced effects such as driven motion, and map out the extent of agglomeration dynamics. The results indicate that for average dose rates below $1.06\,\mathrm{kGy}\mathrm{\mu s}^{-1}$ in a time window up to $10\,\mathrm{\mu s}$, it is possible to capture the protein dynamics before the onset of beam induced aggregation. We refer to this approach as correlation before aggregation and demonstrate that MHz-XPCS bridges an important spatio-temporal gap in measurement techniques for biological samples., Comment: 22 pages, 6 figures