From white elephant to Nobel Prize: Dennis Gabor’s wavefront reconstruction

Dennis Gabor devised a new concept for optical imaging in 1947 that went by a variety of names over the following decade: holoscopy, wavefront reconstruction, interference microscopy, diffraction microscopy and Gaboroscopy. A well-connected and creative research engineer, Gabor worked actively to publicize and exploit his concept, but the scheme failed to capture the interest of many researchers. Gabor’s theory was repeatedly deemed unintuitive and baffling; the technique was appraised by his contemporaries to be of dubious practicality and, at best, constrained to a narrow branch of science. By the late 1950s, Gabor’s subject had been assessed by its handful of practitioners to be a white elephant. Nevertheless, the concept was later rehabilitated by the research of Emmett Leith and Juris Upatnieks at the University of Michigan, and Yury Denisyuk at the Vavilov Institute in Leningrad. What had been judged a failure was recast as a success: evaluations of Gabor’s work were transformed during the 1960s, when it was represented as the foundation on which to construct the new and distinctly different subject of holography, a re-evaluation that gained the Nobel Prize for Physics for Gabor alone in 1971. This paper focuses on the difficulties experienced in constructing a meaningful subject, a practical application and a viable technical community from Gabor’s ideas during the decade 1947-1957

Monetary Policy Processes in Postcommunist Romania

This thesis has a twofold aim. It first argues that monetary policy is inherently political because it involves struggles over meaning. It modifies Niebyl’s (1946) conceptual approach with an explicit attention to meaning, advancing a theory/ policy discourse/institutional practices nexus for exploring central banking. It shows that the emergence of leading representations of monetary processes (in Ricardo, Keynes and Friedman) involved discursive struggles during periods of crisis to assign meaning to problems and establish dominant interpretations. Politics and power were not grafted onto policy but were ontologically constitutive of it, shaping specific institutional configurations and practices. Second, this conceptualization is taken to a case study: a critical scrutiny of the role played by the central bank of Romania (NBR) in the reconstitution of the postcommunist Romanian economy as neoliberal economy from 1990 to 2008. The thesis asks what does the central bank do when the state, defined through its central planning legacy, ‘retreats’ from the market? The usual account explains policy success as direct result of commitments to neoliberal (monetarist) principles prescribed by international policy advice. Before 1997, neocommunist governments politically validated a communist legacy: soft budget constraints in the (state) productive sector. Politicized monetary policy decisions produced repeated crises. Afterwards, neoliberal governments gradually institutionalized an autonomous economic sphere, allowing an objective formulation and implementation of stability-orientated monetarist policies. The thesis challenges this orthodoxy. It argues against the attempts to erase politics from monetary policy processes that the above account articulates. Instead, drawing on critical conceptualizations of neoliberalism in its shifting forms, the period under analysis will be (re)interpreted as an ongoing process of neoliberalization, with the central bank an important actor in it. Indeed, the narration of crises identified the NBR as an essential instrument of institutional change and neoliberal ‘policy-making’. Monetarist narratives (ideologically) legitimized neoliberalism and effectively enacted neoliberal principles of monetary governance in the central bank. Thus, before 1997, the central bank functioned as a key vehicle of the neoliberal attack on the state’s capacity to craft economic reform. Since neoliberal institutions (also) take time to build, expanding policy repertoires outside the monetarist range invested the central bank with increasing powers to respond to structural and institutional resistance to neoliberal logics, arising from both communist legacies and ongoing political struggles. After 1997, the central bank’s rationality gradually changed to a constructive phase, normalizing an extralocal mode of economic governance whose distinguishing features will be identified. Institutional practices reconstructed the relationship between money, foreign exchange and treasury markets, subjugating liquidity management to the requirements of financialized accumulation. With financial stability increasingly tied into transnational actors’ choices, the NBR adopted inflation targeting. Nevertheless, inflation-targeting’s promise of stability operated to sideline the destabilizing nature of normalized neoliberal practices of monetary management, clearly evoked by the 2008 crisis. The thesis concludes with policy implications and an agenda for future research

Quantum Holography

We propose to make use of quantum entanglement for extracting holographic information about a remote 3-D object in a confined space which light enters, but from which it cannot escape. Light scattered from the object is detected in this confined space entirely without the benefit of spatial resolution. Quantum holography offers this possibility by virtue of the fourth-order quantum coherence inherent in entangled beams.Comment: 7 pages, submitted to Optics Expres

Rapid Deforestation and Burned Area Detection using Deep Multimodal Learning on Satellite Imagery

Deforestation estimation and fire detection in the Amazon forest poses a significant challenge due to the vast size of the area and the limited accessibility. However, these are crucial problems that lead to severe environmental consequences, including climate change, global warming, and biodiversity loss. To effectively address this problem, multimodal satellite imagery and remote sensing offer a promising solution for estimating deforestation and detecting wildfire in the Amazonia region. This research paper introduces a new curated dataset and a deep learning-based approach to solve these problems using convolutional neural networks (CNNs) and comprehensive data processing techniques. Our dataset includes curated images and diverse channel bands from Sentinel, Landsat, VIIRS, and MODIS satellites. We design the dataset considering different spatial and temporal resolution requirements. Our method successfully achieves high-precision deforestation estimation and burned area detection on unseen images from the region. Our code, models and dataset are open source: https://github.com/h2oai/cvpr-multiearth-deforestation-segmentationComment: CVPR 2023 Workshop on Multimodal Learning for Earth and Environment (MultiEarth

Dihedral Universal Deformations

This article deals with universal deformations of dihedral representations with a particular focus on the question when the universal deformation is dihedral. Results are obtained in three settings: (1) representation theory, (2) algebraic number theory, (3) modularity. As to (1), we prove that the universal deformation is dihedral if all infinitesimal deformations are dihedral. Concerning (2) in the setting of Galois representations of number fields, we give sufficient conditions to ensure that the universal deformation relatively unramified outside a finite set of primes is dihedral, and discuss in how far these conditions are necessary. As side-results, we obtain cases of the unramified Fontaine-Mazur conjecture, and in many cases positively answer a question of Greenberg and Coleman on the splitting behaviour at p of p-adic Galois representations attached to newforms. As to (3), we prove a modularity theorem of the form `R=T' for parallel weight one Hilbert modular forms for cases when the minimal universal deformation is dihedral.Comment: 43 pages; minor corrections and improvements following referee's comment

Transition from phase to generalized synchronization in time-delay systems

The notion of phase synchronization in time-delay systems, exhibiting highly non-phase-coherent attractors, has not been realized yet even though it has been well studied in chaotic dynamical systems without delay. We report the identification of phase synchronization in coupled nonidentical piece-wise linear and in coupled Mackey-Glass time-delay systems with highly non-phase-coherent regimes. We show that there is a transition from non-synchronized behavior to phase and then to generalized synchronization as a function of coupling strength. We have introduced a transformation to capture the phase of the non-phase coherent attractors, which works equally well for both the time-delay systems. The instantaneous phases of the above coupled systems calculated from the transformed attractors satisfy both the phase and mean frequency locking conditions. These transitions are also characterized in terms of recurrence based indices, namely generalized autocorrelation function $P(t)$, correlation of probability of recurrence (CPR), joint probability of recurrence (JPR) and similarity of probability of recurrence (SPR). We have quantified the different synchronization regimes in terms of these indices. The existence of phase synchronization is also characterized by typical transitions in the Lyapunov exponents of the coupled time-delay systems.Comment: Accepted for publication in CHAO

Thermodynamic Properties of Generalized Exclusion Statistics

We analytically calculate some thermodynamic quantities of an ideal $g$-on gas obeying generalized exclusion statistics. We show that the specific heat of a $g$-on gas ($g \neq 0$) vanishes linearly in any dimension as $T \to 0$ when the particle number is conserved and exhibits an interesting dual symmetry that relates the particle-statistics at $g$ to the hole-statistics at $1/g$ at low temperatures. We derive the complete solution for the cluster coefficients $b_l(g)$ as a function of Haldane's statistical interaction $g$ in $D$ dimensions. We also find that the cluster coefficients $b_l(g)$ and the virial coefficients $a_l(g)$ are exactly mirror symmetric ($l$=odd) or antisymmetric ($l$=even) about $g=1/2$. In two dimensions, we completely determine the closed forms about the cluster and the virial coefficients of the generalized exclusion statistics, which exactly agree with the virial coefficients of an anyon gas of linear energies. We show that the $g$-on gas with zero chemical potential shows thermodynamic properties similar to the photon statistics. We discuss some physical implications of our results.Comment: 24 pages, Revtex, Corrected typo