Viktor T. Toth
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View article: Using machine learning to discover correlations in MIMIC high-cadence data sets
Using machine learning to discover correlations in MIMIC high-cadence data sets Open
Using the MIMIC-IV clinical database and, specifically, the related preliminary MIMIC-IV waveform data release, we endeavored to create a machine learning tool in the form of a gated recurrent unit (GRU) neural network. Our goal was to stu…
View article: Peeking Under the Clouds: Is Exoplanet Imaging with the Solar Gravitational Lens Feasible?
Peeking Under the Clouds: Is Exoplanet Imaging with the Solar Gravitational Lens Feasible? Open
Exoplanet imaging using the solar gravitational lens is an enticing prospect. The fundamental physical properties of the lens, including its angular resolution and light amplification, promise exceptional capabilities. These expectations, …
View article: Pushing limits: Probing new gravity using a satellite constellation
Pushing limits: Probing new gravity using a satellite constellation Open
Building upon earlier work, we explore the limits of using a configuration of satellites to measure the trace of the gravitational gradient tensor using intersatellite laser ranging and timing observables without relying on high-precision …
View article: Temporal Coupling of Brain Signals and Fine Motor Output Using Affordable EEG
Temporal Coupling of Brain Signals and Fine Motor Output Using Affordable EEG Open
This study introduces a novel publicly accessible EEG dataset, acquired through an evoked motor execution paradigm, with a primary objective to examine the relationship between frequency activity of the sensorimotor cortex and index finger…
View article: Metric symmetry by design in general relativity
Metric symmetry by design in general relativity Open
The usual derivation of Einstein’s field equations from the Einstein–Hilbert action is performed by silently assuming the metric tensor’s symmetric character. If this symmetry is not assumed, the result is a new theory, such as Einstein’s …
View article: Is graviton shot noise detectable?
Is graviton shot noise detectable? Open
Direct detection of gravitons in gravitational experiments, including gravitational wave observatories, has been all but ruled out given the weak coupling between the gravitational field and matter. Here we propose an alternative: looking …
View article: Implications of the Milky Way Declining Rotation Curve
Implications of the Milky Way Declining Rotation Curve Open
Almost all spiral galaxies have been observed to have flattening rotation curves. The new Gaia DR3 released data shows a Milky Way sharply Keplerian declining rotation curve, starting at $\sim 16$ kpc and ending at 26.5 kpc. The data reduc…
View article: Non-local redundancy: Erasure coding and dispersed replicas for robust retrieval in the Swarm peer-to-peer network
Non-local redundancy: Erasure coding and dispersed replicas for robust retrieval in the Swarm peer-to-peer network Open
This paper describes in detail how erasure codes are implemented in the Swarm system. First, in Section 1, we introduce erasure codes, and show how to apply them to files in Swarm (Section 2). In Section 3, we introduce security levels of …
View article: A Collection of German Science Interests in the Next Generation Very Large Array
A Collection of German Science Interests in the Next Generation Very Large Array Open
The Next Generation Very Large Array (ngVLA) is a planned radio interferometer providing unprecedented sensitivity at wavelengths between 21 cm and 3 mm. Its 263 antenna element array will be spatially distributed across North America to e…
View article: Scalar–tensor–vector–gravity and NGC-1277
Scalar–tensor–vector–gravity and NGC-1277 Open
NGC1277 is a compact but massive lenticular galaxy that shows no signs of the presence of dark matter. We find that this galaxy’s behaviour is consistent not only with Newtonian dynamics, but also with the predictions of scalar–tensor–vect…
View article: Imaging with a gravitational lens: the geometric view
Imaging with a gravitational lens: the geometric view Open
We investigate imaging point sources with a monopole gravitational lens, such as the Solar Gravitational Lens in the geometric optics limit. We compute the light amplification of the lens used in conjunction with a telescope featuring a ci…
View article: Non-coplanar gravitational lenses and the "communication bridge"
Non-coplanar gravitational lenses and the "communication bridge" Open
We investigate the propagation of light signals across multiple gravitational lenses, with particular emphasis on the "communication bridge" scenario of two lenses with collinear source and observer. The lenses are assumed to be non-coplan…
View article: Imaging with a gravitational lens: the geometric view
Imaging with a gravitational lens: the geometric view Open
We investigate imaging point sources with a monopole gravitational lens, such as the Solar Gravitational Lens in the geometric optics limit. We compute the light amplification of the lens used in conjunction with a telescope featuring a ci…
View article: Gravitational anomaly detection using a satellite constellation: Analysis and simulation
Gravitational anomaly detection using a satellite constellation: Analysis and simulation Open
We investigate the utility of a constellation of four satellites in heliocentric orbit, equipped with accurate means to measure intersatellite ranges, round-trip times and phases of signals coherently retransmitted between members of the c…
View article: Field theory with the Maxima computer algebra system
Field theory with the Maxima computer algebra system Open
The Maxima computer algebra system, the open-source successor to MACSYMA, the first general-purpose computer algebra system that was initially developed at the Massachusetts Institute of Technology in the late 1960s and later distributed b…
View article: Scalar-tensor-vector-gravity and NGC-1277
Scalar-tensor-vector-gravity and NGC-1277 Open
NGC1277 is a compact but massive lenticular galaxy that shows no signs of the presence of dark matter. We find that this galaxy's behavior is consistent not only with Newtonian dynamics, but also with the predictions of Scalar--Tensor--Vec…
View article: Imaging rotating and orbiting exoplanets with the solar gravitational lens
Imaging rotating and orbiting exoplanets with the solar gravitational lens Open
We utilize the well-established properties of the solar gravitational lens (SGL) to consider realistic observational scenarios. Actual exoplanets, which may be the target of an SGL observational campaign, are not stationary. Their appearan…
View article: Science opportunities with solar sailing smallsats
Science opportunities with solar sailing smallsats Open
Recently, we witnessed how the synergy of small satellite technology and solar sailing propulsion enables new missions. Together, small satellites with lightweight instruments and solar sails offer affordable access to deep regions of the …
View article: Spherical harmonics representation of the gravitational phase shift
Spherical harmonics representation of the gravitational phase shift Open
We investigate the general relativistic phase of an electromagnetic wave as it propagates in the gravitational field of the Earth, which is modeled as an isolated, weakly aspherical gravitating body. We introduce coordinate systems to desc…
View article: Mission Architecture to Reach and Operate at the Focal Region of the Solar Gravitational Lens
Mission Architecture to Reach and Operate at the Focal Region of the Solar Gravitational Lens Open
We present initial results of an engineering study on the feasibility of a space mission to the focal region of the solar gravitational lens (SGL). The mission goal is to conduct exoplanet imaging operations at heliocentric distances in th…
View article: Evolving Morphology of Resolved Stellar Einstein Rings
Evolving Morphology of Resolved Stellar Einstein Rings Open
We consider strong gravitational lensing by nearby stars. Using our wave-optical treatment of lensing phenomena, we study Einstein rings that may form around nearby stellar lenses. It is remarkable that these rings are bright and large eno…
View article: Imaging faint sources with the extended solar gravitational lens
Imaging faint sources with the extended solar gravitational lens Open
We consider resolved imaging of faint sources with the solar gravitational lens (SGL) while treating the Sun as an extended gravitating body. We use our new diffraction integral that describes how a spherical electromagnetic wave is modifi…
View article: Navigating stellar wobbles for imaging with the solar gravitational lens
Navigating stellar wobbles for imaging with the solar gravitational lens Open
The solar gravitational lens (SGL) offers unique capabilities for direct high-resolution imaging of faint, distant objects, such as exoplanets. For that purpose, in the near future, a spacecraft carrying a meter-class telescope with a sola…
View article: Organ- and function-specific anatomical organization of the vagus nerve
Organ- and function-specific anatomical organization of the vagus nerve Open
Vagus nerve stimulation (VNS) activates vagal fibers to modulate organ function and treat organ conditions. VNS is currently delivered in a non-selective manner, often resulting in reduced efficacy and side effects. Development of selectiv…
View article: Evolving morphology of resolved stellar Einstein rings
Evolving morphology of resolved stellar Einstein rings Open
We consider strong gravitational lensing by nearby stars. Using our wave-optical treatment of lensing phenomena, we study Einstein rings that may form around nearby stellar lenses. It is remarkable that these rings are bright and large eno…
View article: Spectrally resolved imaging with the solar gravitational lens
Spectrally resolved imaging with the solar gravitational lens Open
We consider the optical properties of the solar gravitational lens (SGL) treating the Sun as a massive compact body. Using our previously developed wave-optical treatment of the SGL, we convolve it with a thin-lens representing an optical …
View article: Efficient trace-free decomposition of symmetric tensors of arbitrary rank
Efficient trace-free decomposition of symmetric tensors of arbitrary rank Open
Symmetric trace-free tensors are used in many areas of physics, including electromagnetism, relativistic celestial mechanics and geodesy, as well as in the study of gravitational radiation and gravitational lensing. Their use allows integr…
View article: A mission architecture to reach and operate at the focal region of the solar gravitational lens
A mission architecture to reach and operate at the focal region of the solar gravitational lens Open
We present initial results of an ongoing engineering study on the feasibility of a space mission to the focal region of the solar gravitational lens (SGL). The mission goal is to conduct exoplanet imaging operations at heliocentric distanc…
View article: Recovering the mass distribution of an extended gravitational lens
Recovering the mass distribution of an extended gravitational lens Open
We investigate the possibility of determining the mass distribution of a gravitational lens via lensing observations. We consider an extended, compact gravitational lens, representing its static external gravitational potential via an infi…
View article: Resolved imaging of exoplanets with the solar gravitational lens
Resolved imaging of exoplanets with the solar gravitational lens Open
We discuss the feasibility of direct multipixel imaging of exoplanets with the solar gravitational lens (SGL) in the context of a realistic deep space mission. For this, we consider an optical telescope, placed in the image plane that form…