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Light sterile neutrinos, left-right symmetry, and 0νββ decay
No full textWe investigate neutrinoless double beta (0νββ) decay rates in minimal left-right symmetric models in presence of relatively light right-handed neutrinos. By use of an effective field theory approach, we systematically include all contributions in the model as well as the dependence of the decay amplitude on the masses of right-handed neutrinos. In type-I and type-II seesaw scenarios, we analyze the impact of right-handed neutrinos heavier than about 10 MeV, showing that this effect can lead to a detection of 0νββ decay in the next-generation experiments even for the normal hierarchy and a relatively large right-handed scale set by the mass of hypothetical right-handed gauge bosons. Finally, we comment on a possible connection between light right-handed neutrinos and the strong CP problem
Brillouin-based radio frequency sources
No full textHigh frequency, low-noise RF sources are of great importance for fundamental science as well as many applications ranging from sensing to communications and RADAR to name a few. This chapter describes the chronological development of radiofrequency sources harnessing photonics and highlights the role Brillouin scattering played in their evolution, starting with fiber-based approaches toward small footprint chip-based schemes. We will provide key performance metrics to provide the reader with enough context to follow the discussion and comparisons of the different schemes. At the end of the chapter, we give a perspective on current trends and future directions
Sharp hierarchical upper bounds on the critical two-point function for long-range percolation on ℤᵈ
No full textConsider long-range Bernoulli percolation on ℤᵈ in which we connect each pair of distinct points x and y by an edge with probability 1 − exp(−β‖x − y‖^(−d−α)), where α > 0 is fixed and β ⩾ 0 is a parameter. We prove that if 0 < α < d, then the critical two-point function satisfies (1/|Λ_r|)∑_(xϵΛ_(r))P_(β_(c))(0 ↔ x) ≤ r^(−d+a) for every r ⩾ 1, where Λ_r = [−r,r]ᵈ ∩ ℤᵈ. In other words, the critical two-point function on ℤᵈ is always bounded above on average by the critical two-point function on the hierarchical lattice. This upper bound is believed to be sharp for values of α strictly below the crossover value α_(c)(d), where the values of several critical exponents for long-range percolation on ℤᵈ and the hierarchical lattice are believed to be equal
The sulfur solubility minimum and maximum in silicate melt
No full textThe behaviour of sulfur in magmas is complex because it dissolves as both sulfide (S²⁻) and sulfate (S⁶⁺) in silicate melt. An interesting aspect in the behaviour of sulfur is the solubility minima (SSᵐⁱⁿ) and maxima (SSᵐᵃˣ) with varying oxygen fugacity (f_O₂). We use a simple ternary model (silicate–S₂–O₂) to explore the varying f_O₂ paths where these phenomena occur. Both SSᵐⁱⁿ and SSᵐᵃˣ occur when S²⁻ and S⁶⁺ are present in the silicate melt in similar quantities due to the differing solubility mechanisms of these species. At constant T, a minimum in dissolved total S content in vapour-saturated silicate melt (w^(m)_(S_T)) occurs along paths of increasing f_O₂ and either constant f_S₂ or P. For paths on which (w^(m)_(S_T)) is held constant with increasing f_O₂, the SSᵐⁱⁿ is expressed as a maximum in P. The SSᵐⁱⁿ occurs when the fraction of S⁶⁺ in the melt ([S⁶⁺/S_(T)]ᵐ) is 0.25 for constant f_S₂ and [S⁶⁺/S_(T)]ᵐ ≅ 0.75 for constant (w^(m)_(S_T)) and P. A minimum in (w^(m)_(S_T)) is not encountered during closed- or open-system depressurisation in the simple system we modelled. However, the SSᵐⁱⁿ marks a change from reduction to oxidation during degassing. Various SSᵐᵃˣ occur when the silicate melt is multiply-saturated with at least two phases: vapour, sulfide melt, and/or anhydrite. The SSᵐⁱⁿ and SSᵐᵃˣ are important features of magmatic process involving S, such as mantle melting, magma mixing, and degassing. These concepts influence calculations of the pressures of vapour-saturation, f_O₂, and SO₂ emissions using melt inclusions
1st Place Solution of The Robust Vision Challenge 2022 Semantic Segmentation Track
No full textThis report describes the winning solution to the Robust Vision Challenge (RVC) semantic segmentation track at ECCV 2022. Our method adopts the FAN-B-Hybrid model as the encoder and uses SegFormer as the segmentation framework. The model is trained on a composite dataset consisting of images from 9 datasets (ADE20K, Cityscapes, Mapillary Vistas, ScanNet, VIPER, WildDash 2, IDD, BDD, and COCO) with a simple dataset balancing strategy. All the original labels are projected to a 256-class unified label space, and the model is trained using a cross-entropy loss. Without significant hyperparameter tuning or any specific loss weighting, our solution ranks the first place on all the testing semantic segmentation benchmarks from multiple domains (ADE20K, Cityscapes, Mapillary Vistas, ScanNet, VIPER, and WildDash 2). The proposed method can serve as a strong baseline for the multi-domain segmentation task and benefit future works. Code will be available at https://github.com/lambert-x/RVC_Segmentatio
Group coset monogamy games and an application to device-independent continuous-variable QKD
No full textWe develop an extension of a recently introduced subspace coset state monogamy-of-entanglement game [Coladangelo, Liu, Liu, and Zhandry; Crypto'21] to general group coset states, which are uniform superpositions over elements of a subgroup to which has been applied a group-theoretic generalization of the quantum one-time pad. We give a general bound on the winning probability of a monogamy game constructed from subgroup coset states that applies to a wide range of finite and infinite groups. To study the infinite-group case, we use and further develop a measure-theoretic formalism that allows us to express continuous-variable measurements as operator-valued generalizations of probability measures.
We apply the monogamy game bound to various physically relevant groups, yielding realizations of the game in continuous-variable modes as well as in rotational states of a polyatomic molecule. We obtain explicit strong bounds in the case of specific group-space and subgroup combinations. As an application, we provide the first proof of one sided-device independent security of a squeezed-state continuous-variable quantum key distribution protocol against general coherent attacks
Second Order Ensemble Langevin Method for Sampling and Inverse Problems
No full textWe propose a sampling method based on an ensemble approximation of second order Langevin dynamics. The log target density is appended with a quadratic term in an auxiliary momentum variable and damped-driven Hamiltonian dynamics introduced; the resulting stochastic differential equation is invariant to the Gibbs measure, with marginal on the position coordinates given by the target. A preconditioner based on covariance under the law of the dynamics does not change this invariance property, and is introduced to accelerate convergence to the Gibbs measure. The resulting mean-field dynamics may be approximated by an ensemble method; this results in a gradient-free and affine-invariant stochastic dynamical system. Numerical results demonstrate its potential as the basis for a numerical sampler in Bayesian inverse problems
Spectral control of nonclassical light pulses using an integrated thin-film lithium niobate modulator
No full textManipulating the frequency and bandwidth of nonclassical light is essential for implementing frequency-encoded/multiplexed quantum computation, communication, and networking protocols, and for bridging spectral mismatch among various quantum systems. However, quantum spectral control requires a strong nonlinearity mediated by light, microwave, or acoustics, which is challenging to realize with high efficiency, low noise, and on an integrated chip. Here, we demonstrate both frequency shifting and bandwidth compression of heralded single-photon pulses using an integrated thin-film lithium niobate (TFLN) phase modulator. We achieve record-high electro-optic frequency shearing of telecom single photons over terahertz range (±641 GHz or ±5.2 nm), enabling high visibility quantum interference between frequency-nondegenerate photon pairs. We further operate the modulator as a time lens and demonstrate over eighteen-fold (6.55 nm to 0.35 nm) bandwidth compression of single photons. Our results showcase the viability and promise of on-chip quantum spectral control for scalable photonic quantum information processing
Mars Science Laboratory CheMin Data From the Glen Torridon Region and the Significance of Lake-Groundwater Interactions in Interpreting Mineralogy and Sedimentary History
No full textThe Glen Torridon (GT) region in Gale crater, Mars is a region with strong clay mineral signatures inferred from orbital spectroscopy. The CheMin X-ray diffraction (XRD) instrument onboard the Mars Science Laboratory rover, Curiosity, measured some of the highest clay mineral abundances to date within GT, complementing the orbital detections. GT may also be unique because in the XRD patterns of some samples, CheMin identified new phases, including: (a) Fe-carbonates, and (b) a phase with a novel peak at 9.2 Å. Fe-carbonates have been previously suggested from other instruments onboard, but this is the first definitive reporting by CheMin of Fe-carbonate. This new phase with a 9.2 Å reflection has never been observed in Gale crater and may be a new mineral for Mars, but discrete identification still remains enigmatic because no single phase on Earth is able to account for all of the GT mineralogical, geochemical, and sedimentological constraints. Here, we modeled XRD profiles and propose an interstratified clay mineral, specifically greenalite-minnesotaite, as a reasonable candidate. The coexistence of Fe-carbonate and Fe-rich clay minerals in the GT samples supports a conceptual model of a lacustrine groundwater mixing environment. Groundwater interaction with percolating lake waters in the sediments is common in terrestrial lacustrine settings, and the diffusion of two distinct water bodies within the subsurface can create a geochemical gradient and unique mineral front in the sediments. Ultimately, the proximity to this mixing zone may have controlled the secondary minerals preserved in sedimentary rocks exposed in GT
Feedback capacity of Gaussian channels with memory
No full textWe consider the feedback capacity of a MIMO channel whose channel output is given by a linear state-space model driven by the channel inputs and a Gaussian process. The generality of our state-space model subsumes all previous studied models such as additive channels with colored Gaussian noise, and channels with an arbitrary dependence on previous channel inputs or outputs. The main result is a computable feedback capacity expression that is given as a convex optimization problem subject to a detectability condition. We demonstrate the capacity result on the auto-regressive Gaussian noise channel, where we show that even a single time-instance delay in the feedback reduces the feedback capacity significantly in the stationary regime. On the other hand, for large regression parameters (in the non-stationary regime), the feedback capacity can be approached with delayed feedback. Finally, we show that the detectability condition is satisfied for scalar models and conjecture that it is true for MIMO models