The Fermilab Holometer in Illinois is intended to be the world's most sensitive laser interferometer, surpassing the sensitivity of the GEO600 and LIGO systems, and theoretically able to detect holographic fluctuations in spacetime.[1][2][3]
According to the director of the project, the Holometer should be capable of detecting fluctuations in the light of a single attometer, meeting or exceeding the sensitivity required to detect the smallest units in the universe called Planck units.[1] Fermilab states: "Everyone is familiar these days with the blurry and pixelated images, or noisy sound transmission, associated with poor internet bandwidth. The Holometer seeks to detect the equivalent blurriness or noise in reality itself, associated with the ultimate frequency limit imposed by nature."[2]
Craig Hogan, a particle astrophysicist at Fermilab, states about the experiment, "What we’re looking for is when the lasers lose step with each other. We’re trying to detect the smallest unit in the universe. This is really great fun, a sort of old-fashioned physics experiment where you don’t know what the result will be."
Experimental physicist Hartmut Grote of the Max Planck Institute in Germany states that although he is skeptical that the apparatus will successfully detect the holographic fluctuations, if the experiment is successful "it would be a very strong impact to one of the most open questions in fundamental physics. It would be the first proof that space-time, the fabric of the universe, is quantized."[1]
Holometer has started, in 2014, collecting data that will help determine whether the universe fits the holographic principle.[4] The hypothesis that holographic noise may be observed in this manner has been criticized on the grounds that the theoretical framework used to derive the noise violates Lorentz-invariance. Lorentz-invariance violation is however very strongly constrained already, an issue that has been very unsatisfactorily addressed in the mathematical treatment.[5]
The Fermilab holometer has found also other uses than studying the holographic fluctuations of spacetime. It has shown constraints on the existence of high-frequency gravitational waves and primordial black holes. [6]
Experimental description
The Holometer will consist of two 39 m arm-length power-recycled Michelson interferometers, similar to the LIGO instruments. The interferometers will be able to be operated in two spatial configurations, termed "nested" and "back-to-back".[7] According to Hogan's hypothesis, in the nested configuration the interferometers' beamsplitters should appear to wander in step with each other (that is, the wandering should be correlated); conversely, in the back-to-back configuration any wandering of the beamsplitters should be uncorrelated.[7] The presence or absence of the correlated wandering effect in each configuration can be determined by cross-correlating the interferometers' outputs.
The experiment started one year of data collection in August 2014.[8] A paper about the project titled Now Broadcasting in Planck Definition by Craig Hogan ends with the statement "We don't know what we will find."[9]
A new result of the experiment released on December 3, 2015, after a year of data collection, has ruled out Hogan's theory of a pixelated universe to a high degree of statistical significance (4.6 sigma). The study found that space-time is not quantized at the scale being measured.[10]
References
Mosher, David (2010-10-28). "World's Most Precise Clocks Could Reveal Universe Is a Hologram". Wired.
"The Fermilab Holometer". Fermi National Accelerator Laboratory. Retrieved 2010-11-01.
Dillow, Clay (2010-10-21). "Fermilab is Building a 'Holometer' to Determine Once and For All Whether Reality Is Just an Illusion". Popular Science.
Do we live in a 2-D hologram? New Fermilab experiment will test the nature of the universe by Andre Salles, Fermilab Office of Communication, on August 26, 2014
Backreaction, Holographic Noise
Weiss; et al. (2017). "MHz gravitational wave constraints with decameter Michelson interferometers". Physical Review D. 95 (63002): 063002. arXiv:1611.05560. Bibcode:2017PhRvD..95f3002C. doi:10.1103/PhysRevD.95.063002. S2CID 59392968.
Cho, Adrian (2012). "Sparks Fly Over Shoestring Test Of 'Holographic Principle'". Science. 336 (6078): 147–9. doi:10.1126/science.336.6078.147. PMID 22499914.
"Do we live in a 2-D hologram? New Fermilab experiment will test the nature of the universe" (Press release). Fermi National Accelerator Laboratory. August 26, 2014. Fermilab Press Release 14-13. "The Holometer experiment ... is expected to gather data over the coming year."
Hogan, Craig (2014-12-04). "Now Broadcasting in Planck Definition". arXiv:1307.2283v2 [quant-ph]. "We don't know what we will find."
Salles, Andre (2015-12-03). "Holometer rules out first theory of space-time correlations". Fermilab. Retrieved 11 December 2015.
vte
Gravitational-wave astronomy
Gravitational wave Gravitational-wave observatory
Detectors
Resonant mass
antennas
Active
NAUTILUS (IGEC) AURIGA (IGEC) MiniGRAIL Mario Schenberg
Past
EXPLORER (IGEC) ALLEGRO (IGEC) NIOBE (IGEC) Stanford gravitational wave detector ALTAIR GEOGRAV AGATA Weber bar
Proposed
Past proposals
GRAIL (downsized to MiniGRAIL) TIGA SFERA Graviton (downsized to Mario Schenberg)
Ground-based
Interferometers
Active
AIGO (ACIGA) CLIO Fermilab holometer GEO600 Advanced LIGO (LIGO Scientific Collaboration) KAGRA Advanced Virgo (European Gravitational Observatory)
Past
TAMA 300 TAMA 20, later known as LISM TENKO-100 Caltech 40m interferometer
Planned
INDIGO (LIGO-India)
Proposed
Cosmic Explorer Einstein Telescope
Past proposals
AIGO (LIGO-Australia)
Space-based
interferometers
Planned
LISA
Proposed
Big Bang Observer DECIGO TianQin
Pulsar timing arrays
EPTA IPTA NANOGrav PPTA
Data analysis
Einstein@Home PyCBC Zooniverse: Gravity Spy
Observations
Events
List of observations First observation (GW150914) GW151012 GW151226 GW170104 GW170608 GW170729 GW170809 GW170814 GW170817 (first neutron star merger) GW170818 GW170823 GW190412 GW190521 (first-ever light from bh-bh merger) GW190814 (first-ever "mass gap" collision)
Methods
Direct detection
Laser interferometers Resonant mass detectors Proposed: Atom interferometers Indirect detection
B-modes of CMB Pulsar timing array Binary pulsar
Theory
General relativity Tests of general relativity Metric theories Graviton
Effects / properties
Polarization Spin-flip Redshift Travel with speed of light h strain Chirp signal (chirp mass) Carried energy
Types / sources
Stochastic
Cosmic inflation-quantum fluctuation Phase transition Binary inspiral
Supermassive black holes Stellar black holes Neutron stars EMRI Continuous
Rotating neutron star Burst
Supernova or from unknown sources Hypothesis
Colliding cosmic string and other unknown sources
Hellenica World - Scientific Library
Retrieved from "http://en.wikipedia.org/"
All text is available under the terms of the GNU Free Documentation License
