Constraining the topology of the universe.

Phys Rev Lett

Department of Physics, Montana State University, Bozeman, Montana 59717, USA.

Published: May 2004

The first year data from the Wilkinson Microwave Anisotropy Probe are used to place stringent constraints on the topology of the Universe. We search for pairs of circles on the sky with similar temperature patterns along each circle. We restrict the search to back-to-back circle pairs, and to nearly back-to-back circle pairs, as this covers the majority of the topologies that one might hope to detect in a nearly flat universe. We do not find any matched circles with radius greater than 25 degrees. For a wide class of models, the nondetection rules out the possibility that we live in a universe with topology scale smaller than 24 Gpc.

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.92.201302DOI Listing

Publication Analysis

Top Keywords

topology universe
8
back-to-back circle
8
circle pairs
8
constraining topology
4
universe
4
universe year
4
year data
4
data wilkinson
4
wilkinson microwave
4
microwave anisotropy
4

Similar Publications

Emergent Symmetry and Valley Chern Insulator in Twisted Double-Bilayer Graphene.

Phys Rev Lett

December 2024

Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA.

Theoretical calculations show that twisted double bilayer graphene (TDBG) under a transverse electric field develops a valley Chern number 2 at charge neutrality. Using thermodynamic and thermal activation measurements we report the experimental observation of a universal closing of the charge neutrality gap in the Hofstadter spectrum of TDBG at 1/2 magnetic flux per unit cell, in agreement with theoretical predictions for a valley Chern number 2 gap. Our theoretical analysis of the experimental data shows that the interaction energy, while larger than the flat-band bandwidth in TDBG near 1° does not alter the emergent valley symmetry or the single-particle band topology.

View Article and Find Full Text PDF

Millimeter-wave and terahertz integrated circuits and chips are expected to serve as the backbone for future wireless networks and high resolution sensing. However, design of these integrated circuits and chips can be quite complex, requiring years of human expertise, careful tailoring of hand crafted circuit topologies and co-design with parameterized and pre-selected templates of electromagnetic structures. These structures (radiative and non-radiative, single-port and multi-ports) are subsequently optimized through ad-hoc methods and parameter sweeps.

View Article and Find Full Text PDF

Full 2023-24 season results of universal prophylaxis with nirsevimab in Galicia, Spain: the NIRSE-GAL study.

Lancet Infect Dis

December 2024

Genetics, Vaccines and Infectious Diseases Research Group, Instituto de Investigación Sanitaria de Santiago de Compostela, Santiago de Compostela, Galicia, Spain; WHO Collaborating Centre for Vaccine Safety, Santiago de Compostela, Galicia, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain; Department of Forensic Science, Pathological Anatomy, Gynaecology and Obstetrics and Paediatrics, University of Santiago de Compostela, Santiago de Compostela, Galicia, Spain; Translational Pediatrics and Infectious Diseases, Hospital Clínico Universitario de Santiago, 15701 Santiago de Compostela, Galicia, Spain. Electronic address:

View Article and Find Full Text PDF

A universal strategy for decoupling stiffness and extensibility of polymer networks.

Sci Adv

November 2024

Soft Biomatter Laboratory, Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904, USA.

Since the invention of polymer networks such as cross-linked natural rubber in the 19th century, it has been a dogma that stiffer networks are less stretchable. We report a universal strategy for decoupling the stiffness and extensibility of single-network elastomers. Instead of using linear polymers as network strands, we use foldable bottlebrush polymers, which feature a collapsed backbone grafted with many linear side chains.

View Article and Find Full Text PDF

Evolution and function of chromatin domains across the tree of life.

Nat Struct Mol Biol

December 2024

Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Center for Regenerative Therapies, Berlin, Germany.

Article Synopsis
  • - The organization of genomes in all organisms is crucial for efficient function, and recent Hi-C methods allow us to explore the 3D arrangement of chromatin across various species.
  • - This review compares chromatin folding in bacteria, archaea, mammals, and plants, highlighting both similarities and differences that shed light on the evolution and function of spatial chromatin domains.
  • - The study reveals that while 3D chromatin structure is ancient and plays a key role in gene regulation, evolutionary changes can lead to significant variations in genome organization across different organisms.
View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!