We experimentally demonstrate optoacoustic cooling via stimulated Brillouin-Mandelstam scattering in a 50 cm-long tapered photonic crystal fiber. For a 7.38 GHz acoustic mode, a cooling rate of 219 K from room temperature has been achieved. As anti-Stokes and Stokes Brillouin processes naturally break the symmetry of phonon cooling and heating, resolved sideband schemes are not necessary. The experiments pave the way to explore the classical to quantum transition for macroscopic objects and could enable new quantum technologies in terms of storage and repeater schemes.

Laura Blázquez Martínez Philipp Wiedemann Changlong Zhu Andreas Geilen Birgit Stiller

Raney extensions and strictly zero-dimensional biframes both faithfully extend the dual of the category of $T_0$ spaces. We use tools from pointfree topology to look at the connection between the two. Raney extensions may be equivalently described as pairs $(L,\mathcal{F})$ where $L$ is a frame and $\mathcal{F}\subseteq \mathcal{S}_{o}(L)$ a subcolocale containing all open sublocales. Here, $\mathcal{S}_o(L)$ is the collection of all intersections of open sublocales of $L$. Similarly, a strictly zero-dimensional biframe is a pair $(L,\mathcal{D})$ where $\mathcal{D}\subseteq \mathcal{S}(L)$ is a codense subcolocale. We show that there is an adjunction between certain subcolocales of $\mathcal{S}_o(L)$ and codense subcolocales of $\mathcal{S}(L)$. We show that the adjunction maximally restricts to an order-isomorphism between the subcolocales of $\mathcal{S}_o(L)$ where the joins of open sublocales distribute over binary meets, which we call the proper subcolocales, and what we call the essential codense subcolocales. As an application of our main result, we establish a bijection between proper Raney extensions and the strictly zero-dimensional biframes $(L_1,L_2,L)$ such that $L$ is an essential extension of $L_2$ in the category of frames. We show that this correspondence cannot be made functorial in the obvious way, as a frame morphism $f:L\to M$ may lift to a map $f:(L,\mathcal{F})\to (L,\mathcal{G})$ of Raney extensions without lifting to a map between the associated strictly zero-dimensional biframes.

Anna Laura Suarez

Cryogenic calorimeters, also known as bolometers, are among the leading technologies for searching for rare events. The CUPID experiment is exploiting this technology to deploy a tonne-scale detector to search for neutrinoless double-beta decay of $^{100}$Mo. The CUPID collaboration proposed an innovative approach to assembling bolometers in a stacked configuration, held in position solely by gravity. This gravity-based assembly method is unprecedented in the field of bolometers and offers several advantages, including relaxed mechanical tolerances and simplified construction. To assess and optimize its performance, we constructed a medium-scale prototype hosting 28 Li$_2$MoO$_4$ crystals and 30 Ge light detectors, both operated as cryogenic calorimeters at the Laboratori Nazionali del Gran Sasso (Italy). Despite an unexpected excess of noise in the light detectors, the results of this test proved (i) a thermal stability better than $\pm$0.5 mK at 10 mK, (ii) a good energy resolution of Li$_2$MoO$_4$ bolometers, (6.6 $\pm$ 2.2) keV FWHM at 2615 keV, and (iii) a Li$_2$MoO$_4$ light yield measured by the closest light detector of 0.36 keV/MeV, sufficient to guarantee the particle identification requested by CUPID.

The CUPID Collaboration K. Alfonso A. Armatol C. Augier F. T. Avignone III O. Azzolini A. S. Barabash G. Bari A. Barresi D. Baudin F. Bellini G. Benato L. Benussi V. Berest M. Beretta M. Bettelli M. Biassoni J. Billard F. Boffelli V. Boldrini E. D. Brandani C. Brofferio C. Bucci M. Buchynska J. Camilleri A. Campani J. Cao C. Capelli S. Capelli V. Caracciolo L. Cardani P. Carniti N. Casali E. Celi C. Chang M. Chapellier H. Chen D. Chiesa D. Cintas M. Clemenza I. Colantoni S. Copello O. Cremonesi R. J. Creswick A. D'Addabbo I. Dafinei F. A. Danevich F. De Dominicis M. De Jesus P. de Marcillac S. Dell'Oro S. Di Domizio S. Di Lorenzo V. Dompè A. Drobizhev L. Dumoulin G. Fantini M. El Idrissi M. Faverzani E. Ferri F. Ferri F. Ferroni E. Figueroa-Feliciano J. Formaggio A. Franceschi S. Fu B. K. Fujikawa J. Gascon S. Ghislandi A. Giachero M. Girola L. Gironi A. Giuliani P. Gorla C. Gotti C. Grant P. Gras P. V. Guillaumon T. D. Gutierrez K. Han E. V. Hansen K. M. Heeger D. L. Helis H. Z. Huang M. T. Hurst L. Imbert A. Juillard G. Karapetrov G. Keppel H. Khalife V. V. Kobychev Yu. G. Kolomensky R. Kowalski H. Lattaud M. Lefevre M. Lisovenko R. Liu Y. Liu P. Loaiza L. Ma F. Mancarella N. Manenti A. Mariani L. Marini S. Marnieros M. Martinez R. H. Maruyama Ph. Mas D. Mayer G. Mazzitelli E. Mazzola Y. Mei M. N. Moore S. Morganti T. Napolitano M. Nastasi J. Nikkel C. Nones E. B. Norman V. Novosad I. Nutini T. O'Donnell E. Olivieri M. Olmi B. T. Oregui S. Pagan M. Pageot L. Pagnanini D. Pasciuto L. Pattavina M. Pavan Ò. Penek H. Peng G. Pessina V. Pettinacci C. Pira S. Pirro O. Pochon D. V. Poda T. Polakovic O. G. Polischuk E. G. Pottebaum S. Pozzi E. Previtali A. Puiu S. Puranam S. Quitadamo A. Rappoldi G. L. Raselli A. Ressa R. Rizzoli C. Rosenfeld P. Rosier M. Rossella J. A. Scarpaci B. Schmidt R. Serino A. Shaikina K. Shang V. Sharma V. N. Shlegel V. Singh M. Sisti P. Slocum D. Speller P. T. Surukuchi L. Taffarello S. Tomassini C. Tomei A. Torres J. A. Torres D. Tozzi V. I. Tretyak D. Trotta M. Velazquez K. J. Vetter S. L. Wagaarachchi G. Wang L. Wang R. Wang B. Welliver J. Wilson K. Wilson L. A. Winslow F. Xie M. Xue J. Yang V. Yefremenko V. I. Umatov M. M. Zarytskyy T. Zhu A. Zolotarova S. Zucchelli

Given an almost complex manifold (M, J), we study complex connections with trivial holonomy and such that the corresponding torsion is either of type (2,0) or of type (1,1) with respect to J. Such connections arise naturally when considering Lie groups, and quotients by discrete subgroups, equipped with bi-invariant and abelian complex structures.

A. Andrada M. L. Barberis I. G. Dotti

Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel ~10^(-4) solar masses of material at velocities exceeding 1,000 kilometres per second. However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds, or binary interaction with the nova envelope. Classical novae are now routinely detected in gigaelectronvolt gamma-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the gamma-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion. At the interface between the equatorial and polar regions, we observe synchrotron emission indicative of shocks and relativistic particle acceleration, thereby pinpointing the location of gamma-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae, explaining why many novae are gamma-ray emitters.

Laura Chomiuk Justin D. Linford Jun Yang T. J. O'Brien Zsolt Paragi Amy J. Mioduszewski R. J. Beswick C. C. Cheung Koji Mukai Thomas Nelson Valerio A. R. M. Ribeiro Michael P. Rupen J. L. Sokoloski Jennifer Weston Yong Zheng Michael F. Bode Stewart Eyres Nirupam Roy Gregory B. Taylor

Water is essential for almost every aspect of life on our planet and, unsurprisingly, its properties have been studied in great detail. However, disproportionately little remains known about the electrical properties of interfacial and strongly confined water where its structure deviates from that of bulk water, becoming distinctly layered. The structural change is expected to affect water's conductivity and particularly its polarizability, which in turn modifies intermolecular forces that play a crucial role in many physical and chemical processes. Here we use scanning dielectric microscopy to probe the in-plane electrical properties of water confined between atomically flat surfaces separated by distances down to 1 nm. For confinement exceeding a few nm, water exhibits an in-plane dielectric constant close to that of bulk water and its proton conductivity is notably enhanced, gradually increasing with decreasing water thickness. This trend abruptly changes when the confined water becomes only a few molecules thick. Its in-plane dielectric constant reaches giant, ferroelectric-like values of about 1,000 whereas the conductivity peaks at a few S/m, close to values characteristic of superionic liquids. We attribute the enhancement to strongly disordered hydrogen bonding induced by the few-layer confinement, which facilitates both easier in-plane polarization of molecular dipoles and faster proton exchange. This insight into the electrical properties of nanoconfined water is important for understanding many phenomena that occur at aqueous interfaces and in nanoscale pores.

R. Wang M. Souilamas A. Esfandiar R. Fabregas S. Benaglia H. Nevison-Andrews Q. Yang J. Normansell P. Ares G. Ferrari A. Principi A. K. Geim L. Fumagalli

We present 870 $\mu$m ALMA observations of polarized dust emission toward the Class II protoplanetary disk IM Lup. We find that the orientation of the polarized emission is along the minor axis of the disk, and that the value of the polarization fraction increases steadily toward the center of the disk, reaching a peak value of ~1.1%. All of these characteristics are consistent with models of self-scattering of submillimeter-wave emission from an optically thin inclined disk. The distribution of the polarization position angles across the disk reveals that while the average orientation is along the minor axis, the polarization orientations show a significant spread in angles; this can also be explained by models of pure scattering. We compare the polarization with that of the Class I/II source HL Tau. A comparison of cuts of the polarization fraction across the major and minor axes of both sources reveals that IM Lup has a substantially higher polarization fraction than HL Tau toward the center of the disk. This enhanced polarization fraction could be due a number of factors, including higher optical depth in HL Tau, or scattering by larger dust grains in the more evolved IM Lup disk. However, models yield similar maximum grain sizes for both HL Tau (72 $\mu$m) and IM Lup (61 $\mu$m, this work). This reveals continued tension between grain-size estimates from scattering models and from models of the dust emission spectrum, which find that the bulk of the (unpolarized) emission in disks is most likely due to millimeter (or even centimeter) sized grains.

Charles L. H. Hull Haifeng Yang Zhi-Yun Li Akimasa Kataoka Ian W. Stephens Sean Andrews Xuening Bai L. Ilsedore Cleeves A. Meredith Hughes Leslie Looney Laura M. Pérez David Wilner

A general method for estimating the Yang-Yang ratio, ${\cal R}_{\mu}$, and the coexistence-curve diameter of a model fluid via Monte Carlo simulations is presented on the basis of data for a hard-core square-well (HCSW) fluid and the restricted primitive model (RPM) electrolyte. The isothermal minima of $Q_{L}\equiv< m^{2}>^{2}_{L}/< m^{4}>_{L}$ are evaluated at $T_{c}$ in an $L\times L\times L$ box where $m = \rho - <\rho>_{L}$ is the density fluctuation. The ``complete'' finite-size scaling theory for the $Q_{\scriptsize min}^{\pm}(T_{c};L)$ incorporates pressure mixing in the scaling fields, thereby allowing for a Yang-Yang anomaly.

Young C. Kim

We present an ab initio description of optical and shallow-core x-ray absorption spectroscopies in a unified formalism based on the pseudopotential plane-wave method at the level of the Bethe-Salpeter equation (BSE) within Green's functions theory. We show that norm-conserving pseudopotentials are reliable and accurate not only for valence, but also for semicore electron excitations. In order to validate our approach, we compare BSE absorption spectra obtained with two different codes: the pseudopotential-based code EXC and the all-electron full-potential code Exciting. We take corundum $\alpha$-Al$_2$O$_3$ as an example, being a prototypical material that presents strong electron-hole interactions for both valence and core electron excitations. We analyze in detail the optical absorption spectrum as well as the Al L$_1$ and L$_{2,3}$ edges in terms of anisotropy, crystal local fields, interference and excitonic effects. We perform a thorough inspection of the origin and localization of the lowest-energy excitons, and conclude highlighting the purely electronic character off the pre-edge of L$_1$ and the dichroic nature of the optical and L$_{23}$ spectra.

M. Laura Urquiza Matteo Gatti Francesco Sottile

We introduce a pointfree version of Raney duality. Our objects are \emph{Raney extensions} of frames, pairs $(L,C)$ where $C$ is a coframe and $L\subseteq C$ is a subframe that meet-generates it and whose embedding preserves strongly exact meets. We show that there is a dual adjunction between $\mathbf{Raney}$ and $\mathbf{Top}$, with all $T_0$ spaces as fixpoints, assigning to a space $X$ the pair $(\Omega(X),\mathcal{U}(X))$, with $\mathcal{U}(X)$ are the intersections of open sets. We show that for every Raney extension $(L,C)$ there are subcolocale inclusions $\mathcal{S}_c(L)^{op}\subseteq C\subseteq \mathcal{S}_o(L)$ where these are the opposite of the frame of joins of closed sublocales and the coframe of intersections of open sublocales. We thus exhibit a symmetry between these two well-studied structures in pointfree topology. The spectra of these are, respectively, the classical spectrum $\mathsf{pt}(L)$ of the underlying frame and its $T_D$ spectrum $\mathsf{pt}_D(L)$. This confirms the view advanced in \cite{banaschewskitd} that sobriety and the $T_D$ property are mirror images of each other, and suggests that the symmetry above is a pointfree view of it. All Raney extensions satisfy some variation of the properties \emph{density} and \emph{compactness} from the theory of canonical extensions. We characterize sobriety, the $T_1$, and the $T_D$ axioms in terms of density and compactness of $(\Omega(X),\mathcal{U}(X))$. We characterize frame morphisms $f:L\to M$ that extend to Raney morphisms $\overline{f}:(L,C)\to (M,D)$. We use this result to exhibit the existence of various free and cofree constructions. We use Raney extensions to give a new perspective on canonical extension generalized to frames as well as $T_D$ duality.

Anna Laura Suarez