Cosmic tango between very small and very large


Small volume fluctuations in the early universe explain two major mysteries about the massive structure of the universe, in a cosmic tango of very small and very large. A new study by Penn State researchers used the theory of quantum loop gravity to account for these mysteries, which Einstein’s theory of general relativity considered illogical. Sincerely: Dani Zemba, Penn State

While Einstein’s theories of general relativity can explain a large array of fascinating astrophysics and cosmological phenomena, some aspects of the properties of the universe on the largest scale remain a mystery. A new study using loop quantum cosmology – a theory that uses quantum mechanics, which extends gravity physics beyond Einstein’s theory of general relativity – examines two key mysteries. While the differences in theories occur in the largest part of the scales – much smaller than that of a proton – they have the largest accessible scales in the universe. The study, which appears online in the journal on July 29 Physical review letter, Also provides new predictions about the universe that can test future satellite missions.


While a zoomed-out picture of the universe looks quite similar, it has a large-scale structure, for example because the Milky Way and dark matter are not evenly distributed throughout the universe. The origins of this structure have been traced to the cosmic microwave background (CMB) – tiny inhumanities observed in radiation, when the universe was 380 thousand years old that we can still see today. But the CMB itself has three surprising features that are considered anomalies because they are difficult to explain using known physics.

Donghui Jong, Associate Professor of Astronomy and Astrophysics at Penn State and author of the paper, said, “Given one of these anomalies, it cannot happen that seeing two or more people live in an extraordinary universe. ” “A recent study in the journal Nature Astronomy proposed an explanation for one of these discrepancies that raised many additional concerns, marking a ‘possible crisis in cosmology’. However, quantum loop cosmology Using these, we have naturally resolved two of these inconsistencies, which avoid a potential crisis. ”

Research over the past three decades has greatly improved our understanding of the early universe, including how unnaturalism first arose in the CMB. This inhumanity is a consequence of inevitable quantum fluctuations in the early universe. During a high accelerated phase of expansion at very early times — known as inflation — these primitive, minimalist fluctuations were drawn under the influence of gravity and seeded the observed inequalities in the CMB.

Cosmic tango between very small and very large

Pictures showing the evolution of the universe, according to the paradigm of loop quantum origin developed by scientists at Penn State. Sincerely: Alan Stonebroker p. Singh, Physics 5, 142 (2012); APS / A. Stonebraker

“To understand how primordial seeds were born, we need to take a closer look at the early universe, where Einstein’s theory of general relativity breaks down,” Evan Pugh Professor of Physics, holder of the Eberly Family Chair in Physics, And Director Drs. Abhay Ashtekar said. Penn State Institute for Gravitation and the Cosmos. “Standard inflationary models based on general relativity consider space-time as a smooth continuum. Consider a shirt that looks like a two-dimensional surface, but upon closer inspection you can see that it is densely Woven by packaged one-dimensional threads. In this way, the space-time fabric is actually woven by quantum threads. In accounting for these threads, loop quantum cosmology allows us to go beyond the continuum described by general relativity. Allows where Einstein’s physics breaks down – beyond the Big Bang for example. “

Previous investigations by researchers in the early universe changed the idea of ​​Big Bang eccentricity, where the universe came out of nothing with the Big Bounce, where the current expanding universe emerged from a super-compressed mass that was created when the universe contracted its predecessor. Phase. They found that all the large-scale structures of the universe are accounted for by general relativity, the loop after this big bounce is explained equally by inflation using the equations of quantum cosmology.

In the new study, researchers determined that inflation under loop quantum cosmology also resolves two major anomalies that appear under general relativity.

At the time of the research, Penn State’s postdoctoral researcher and currently postdoctoral researcher at the Texas Advanced Computing Center at the University of Texas at Austin, said, “The initial fluctuations we’re talking about would have been on an incredibly small Planck scale is.” “Planck’s length is about 20 orders of magnitude smaller than the radius of a proton. But this unimaginably small-scale inflation correction simultaneously explains the two anomalies on the largest scale of the universe, much smaller and one cosmic. Tango. Very big. “

The researchers made a fundamental cosmological parameter and new predictions about primordial gravitational waves that could be tested during future satellite missions, including Lightbird and Cosmic Origin Explorer, which will continue to improve our understanding of the early universe.


Size of the Universe: Study can force us to know everything about the universe


more information:
Abhay Ashtekar et al, Reducing Stress in the Cosmic Microwave Background Using Planck-Scale Physics, Physical review letter (2020). DOI: 10.1103 / PhysRevLett.125.051302

Provided by Pennsylvania State University

Quotes: Cosmic tango between very small and very large (2020, 30 July) Retrieved 30 July 2020 from https://phys.org/news/2020-07-cosmic-tango-small-large.html

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