Oliver Zahn | |
---|---|
![]() | |
Nationality | German and American |
Alma mater | Ludwig Maximilian University of Munich (Diploma in Physics, 2003) Harvard-Smithsonian Center for Astrophysics and Heidelberg University (Ph.D., 2007) |
Occupation |
|
Website | www |
Oliver Zahn is US/German theoretical astrophysicist, data scientist, and entrepreneur, best known for developing algorithms for astrophysical data analysis and widely cited discoveries of phenomena in the history of the Universe. He is also known for his more recent work as founder and CEO of Climax Foods, a California-based biotechnology company modeling dairy and other animal products directly from plant ingredients. Prior to becoming an entrepreneur, Zahn directed UC Berkeley's Center for Cosmological Physics alongside George Smoot and Saul Perlmutter and was Head of Data Science at Google [1]
Zahn was born in Munich and studied physics and philosophy at Ludwig Maximilian University of Munich, doing his Diploma thesis in theoretical astrophysics jointly at Max Planck Institute for Astrophysics and New York University, graduating summa cum laude. He went on to do his dissertation work in cosmology at Harvard University, before winning the inaugural prize fellowship at UC Berkeley's Center for Cosmological Physics, [2] funded directly by the 2006 Nobel Prize in Physics. [3]
In 2019, Oliver founded Climax Foods to replace animal foods with dairy and meat directly produced from plants, circumventing the animals' complex metabolisms and thereby reducing greenhouse gases and water use caused by animal agriculture. Climax aims to outcompete animal products by offering zero-compromise alternatives that are purely plant-based, yet indistinguishable in terms of taste and texture, and better than their animal-based competitors in terms of nutrition and price. [4] [5] [6]
Zahn has worked on a broad range of topics in theoretical, computational, and observational astrophysics and cosmology. Working with multiple multi-national collaborations, he has co-authored more than 100 peer-reviewed journal articles with more than 14,000 citations and a h-index of 68. [7]
As an undergraduate at Max Planck Institute for Astrophysics, Zahn studied the early Universe and constrained deviations from the laws of gravity and electro-magnetism during the Big Bang. [8]
While a doctoral student at Harvard University, Zahn and co-authors Smith and Dore detected, for the first time, gravitational lensing in the cosmic microwave background. [9] The finding has since been confirmed by teams analyzing data from the Planck, Polarbear, and SPT telescopes [10] [11] [12]
In a separate series of papers [13] [14] [15] Zahn introduced statistical measures to use redshifted 21 cm radiation to study otherwise inaccessible periods of the Universe's structure formation. He invented a novel simulation framework to study galaxy formation in the cosmic web, yielding orders of magnitude performance gains compared to previous ray tracing frameworks, enabling exploration of much larger parameter spaces.
While leading analyses for the University of Chicago and University of California, Berkeley, based South Pole Telescope collaboration, Zahn and his team showed that the first galaxies formed more explosively than previously thought. [16] [17]
In physical cosmology, the Copernican principle states that humans are not privileged observers of the universe, that observations from the Earth are representative of observations from the average position in the universe. Named for Copernican heliocentrism, it is a working assumption that arises from a modified cosmological extension of Copernicus' argument of a moving Earth.
The cosmic microwave background, or relic radiation, is microwave radiation that fills all space in the observable universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dark. However, a sufficiently sensitive radio telescope detects a faint background glow that is almost uniform and is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The accidental discovery of the CMB in 1965 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s.
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies. Galaxy formation is hypothesized to occur from structure formation theories, as a result of tiny quantum fluctuations in the aftermath of the Big Bang. The simplest model in general agreement with observed phenomena is the Lambda-CDM model—that is, clustering and merging allows galaxies to accumulate mass, determining both their shape and structure. Hydrodynamics simulation, which simulates both baryons and dark matter, is widely used to study galaxy formation and evolution.
In modern physical cosmology, the cosmological principle is the notion that the spatial distribution of matter in the universe is uniformly isotropic and homogeneous when viewed on a large enough scale, since the forces are expected to act equally throughout the universe on a large scale, and should, therefore, produce no observable inequalities in the large-scale structuring over the course of evolution of the matter field that was initially laid down by the Big Bang.
Cosmic strings are hypothetical 1-dimensional topological defects which may have formed during a symmetry-breaking phase transition in the early universe when the topology of the vacuum manifold associated to this symmetry breaking was not simply connected. Their existence was first contemplated by the theoretical physicist Tom Kibble in the 1970s.
The Sunyaev–Zeldovich effect is the spectral distortion of the cosmic microwave background (CMB) through inverse Compton scattering by high-energy electrons in galaxy clusters, in which the low-energy CMB photons receive an average energy boost during collision with the high-energy cluster electrons. Observed distortions of the cosmic microwave background spectrum are used to detect the disturbance of density in the universe. Using the Sunyaev–Zeldovich effect, dense clusters of galaxies have been observed.
In the fields of Big Bang theory and cosmology, reionization is the process that caused electrically neutral atoms in the universe to reionize after the lapse of the "dark ages".
The hydrogen line, 21 centimeter line, or H I line is a spectral line that is created by a change in the energy state of solitary, electrically neutral hydrogen atoms. It is produced by a spin-flip transition, which means the direction of the electron's spin is reversed relative to the spin of the proton. This is a quantum state change between the two hyperfine levels of the hydrogen 1 s ground state. The electromagnetic radiation producing this line has a frequency of 1420.405751768(2) MHz (1.42 GHz), which is equivalent to a wavelength of 21.106114054160(30) cm in a vacuum. According to the Planck–Einstein relation E = hν, the photon emitted by this transition has an energy of 5.8743261841116(81) μeV [9.411708152678(13)×10−25 J]. The constant of proportionality, h, is known as the Planck constant.
The Lambda-CDM, Lambda cold dark matter, or ΛCDM model is a mathematical model of the Big Bang theory with three major components:
The South Pole Telescope (SPT) is a 10-metre (390 in) diameter telescope located at the Amundsen–Scott South Pole Station, Antarctica. The telescope is designed for observations in the microwave, millimeter-wave, and submillimeter-wave regions of the electromagnetic spectrum, with the particular design goal of measuring the faint, diffuse emission from the cosmic microwave background (CMB). Key results include a wide and deep survey of discovering hundreds of clusters of galaxies using the Sunyaev–Zel'dovich effect, a sensitive 5 arcminute CMB power spectrum survey, and the first detection of B-mode polarized CMB.
In astrophysics, dark flow is a controversial hypothesis to explain certain non-random measurements of peculiar velocity of galaxy clusters. The actual measured velocity is the sum of the velocity predicted by Hubble's law plus a possible small velocity flowing in a common direction. Very large scale correlated flow, called bulk flow is proposed in this model to be related to certain models of inflationary cosmology.
In cosmology, the steady-state model or steady state theory is an alternative to the Big Bang theory. In the steady-state model, the density of matter in the expanding universe remains unchanged due to a continuous creation of matter, thus adhering to the perfect cosmological principle, a principle that says that the observable universe is always the same at any time and any place.
Uroš Seljak is a Slovenian cosmologist and a professor of astronomy and physics at University of California, Berkeley. He is particularly well-known for his research in cosmology and approximate Bayesian statistical methods.
POLARBEAR is a cosmic microwave background polarization experiment located in the Atacama Desert of northern Chile in the Antofagasta Region. The POLARBEAR experiment is mounted on the Huan Tran Telescope (HTT) at the James Ax Observatory in the Chajnantor Science Reserve. The HTT is located near the Atacama Cosmology Telescope on the slopes of Cerro Toco at an altitude of nearly 5,200 m (17,100 ft).
The Cosmology Large Angular Scale Surveyor (CLASS) is an array of microwave telescopes at a high-altitude site in the Atacama Desert of Chile as part of the Parque Astronómico de Atacama. The CLASS experiment aims to improve our understanding of cosmic dawn when the first stars turned on, test the theory of cosmic inflation, and distinguish between inflationary models of the very early universe by making precise measurements of the polarization of the Cosmic Microwave Background (CMB) over 65% of the sky at multiple frequencies in the microwave region of the electromagnetic spectrum.
In cosmology, intensity mapping is an observational technique for surveying the large-scale structure of the universe by using the integrated radio emission from unresolved gas clouds.
Rafael Rebolo López is a Spanish astrophysicist. In October 2013 he became the director of the Instituto de Astrofísica de Canarias. He is a professor at the Spanish National Research Council. In 2002 Rebolo became an external professor at the Max Planck Institute for Astronomy and a member of the Max Planck Society.
In cosmological inflation, within the slow-roll paradigm, the Lyth argument places a theoretical upper bound on the amount of gravitational waves produced during inflation, given the amount of departure from the homogeneity of the cosmic microwave background (CMB).
Sultan Hassan is a Sudanese computational astrophysicist and NASA Hubble Fellow.