- Researchers from Australia and France team up for a record-breaking laser transmission.
- The new technique avoids atmospheric interference.
- It can be used to test aspects of Einstein's theory of relativity and advance communications.
Scientists achieved the most stable transmission of a laser signal through the atmosphere ever made, beating a world record. The team managed to send laser signals from one point to another while avoiding interference from the atmosphere. Their very precise method can allow for unprecedented comparisons of the flow of time in separate locations. This can enable scientists to carry out new tests of Einstein's celebrated theory of general relativity, and have wide applications across different fields.
For the record transmission, the researchers combined phase stabilization technology with advanced self-guiding optical terminals. They used two identical phase stabilization systems, which had their transmitters located in one building while receivers were in another. One system used optical terminals to send the optical signal over a 265-meter free-space path between the buildings. Another system transmitted using a 715 meter-long optical fiber cable, essentially to keep tabs on the performance of the free-space link. The terminals were outfitted with mirrors to prevent interference like phase noise and beam wander.
The scientists hailed from Australia's International Centre for Radio Astronomy Research (ICRAR) and the University of Western Australia (UWA), as well as the French National Centre for Space Studies (CNES) and the French metrology lab Systèmes de Référence Temps-Espace (SYRTE) at Paris Observatory.
The study's lead author Benjamin Dix-Matthews, a Ph.D. student at ICRAR and UWA, highlighted the innovation and potential of their technique. "We can correct for atmospheric turbulence in 3-D, that is, left-right, up-down and, critically, along the line of flight," said Dix-Matthews in a press release. "It's as if the moving atmosphere has been removed and doesn't exist. It allows us to send highly stable laser signals through the atmosphere while retaining the quality of the original signal."
Credit: Dix-Matthews, Nature Communications
Block diagram (above) of the experimental link that shows two identical phase stabilization systems on the CNES campus. Both of the systems have their transmitter in the Auger building (local site), and both receivers are located in the Lagrange building (remote site). One transmits the optical signal over a 265 m free-space path in-between the buildings while utilizing tip-tilt active optics terminals. The other transmits using 715 m of optical fiber.
Dr. Sascha Schediwy, ICRAR-UWA senior researcher, envisioned numerous applications for their technology, whose precise performance beats even the best optical atomic clocks. Putting one of these optical terminals on the ground while another one is on a satellite in space would help the exploration of fundamental physics, according to Schediwy. Other applications could extend to testing Einstein's theories with greater precision as well as understanding the time-related changes of fundamental physical constants and making advanced measurements in earth science and geophysics.
Optical communications, a field that utilizes light for sending information, could also benefit. The new tech can improve its data rates by "orders of magnitude," thinks Dr. Schediwy. "The next generation of big data-gathering satellites would be able to get critical information to the ground faster," he added.
Check out the new study in Nature Communications.
Lev Landau (1908-1968) was one of Soviet Union's best physicists. He made contributions to nuclear theory, quantum field theory, and astrophysics, among others. In 1962, he won a Nobel Prize in Physics for developing the mathematical theory of superfluidity. Landau also wrote an immensely influential textbook on physics, teaching generations of scientists.
A brilliant mind, Landau liked to classify everything in his life. He ranked people by their intelligence, beauty (he had a penchant for blondes), contributions to science, how they dressed, and even how they talked – often with a healthy dose of sarcasm.
One of the most famous of Landau's classifications that has been passed down is his ranking of the greatest physicists of the 20th century. Of course, it wouldn't have later physicists, as he died in 1968, but these are arguably the most significant names.
This scale is logarithmic, meaning people ranked as rank 1 contributed ten times more (according to Landau) than people ranked as class 2, and so forth. In other words, the higher the number, the less valuable the physicist.
Here's how this scale broke down:
Rank 0.5 – Albert Einstein (1879 - 1955)
Einstein, the creator of the Theory of General Relativity, is in a class of his own. Landau thought he was by far the greatest mind among a very impressive group that redefined modern physics.
Landau added, however, that if the list was to be expanded to scientists of the previous centuries, Isaac Newton (1643 - 1727), the titan of classical physics, would also join Einstein at first place with 0.5.
Rank 0.5 – Albert Einstein
Albert Einstein With Displaced Children From Concentration Camps. 1949.
Photo by Keystone-France/Gamma-Keystone via Getty Images
Rank 1
The group in this class of the smartest physicists included the top minds that developed the theories of quantum mechanics.
Werner Heisenberg (1901 - 1976) - a German theoretical physicist, who's achieved pop-culture fame by being the name of Walter White's alter ego in Breaking Bad. He is known for the Heiseinberg Uncertainty Principle and his 1932 Nobel Prize award flatly states it was for nothing less than "the creation of quantum mechanics".
Erwin Schrödinger (1887 - 1961) - an Austrian-Irish physicist who gave us the infamous "Schroedinger's Cat" thought experiment and other mind-benders from quantum mechanics. The Nobel-prize-winner's Schrödinger equation calculates the wave function of a system and how it changes over time.
Erwin Schrödinger. 1933.
Paul Dirac (1902 - 1984) - another quantum mechanics giant, this English theoretical physicist shared the 1933 Nobel Prize with Erwin Schrödinger "for the discovery of new productive forms of atomic theory."
Niels Bohr (1885 - 1962) - a Danish physicist who made founder-level additions to what we know of atomic structure and quantum theory, which led to his 1922 Nobel Prize in Physics.
Satyendra Nath Bose (1894 - 1974) - an Indian mathematician and physicist, known for his quantum mechanics work. He collaborated with Einstein to develop the Bose-Einstein statistics and the theory of the Bose–Einstein condensate. Boson particles are named after him.
Satyendra Nath Bose. 1930s.
Eugene Wigner (1902 - 1995) - a Hungarian-American theoretical physicist who received the 1963 Nobel Prize in Physics for work on the theory of the atomic nucleus and the elementary particles. Famously, he took part in the meeting with Leo Szilard and Albert Einstein that led to them writing a letter to President Franklin D. Roosevelt which resulted in the creation of the Manhattan Project.
Louis de Broglie (1892 - 1987) - a French theorist who made key contributions to quantum theory. He proposed the wave nature of electrons, suggesting that all matter has wave properties – an example of the concept of wave-particle duality, central to the theory of quantum mechanics.
Enrico Fermi (1901 - 1954) - an American physicist who's been called the "architect of the nuclear age" as well as the "architect of the Atomic bomb". He also created the world's first nuclear reactor and won the 1938 Nobel Prize in Physics for work on induced radioactivity and for discovering transuranium elements.
Enrico Fermi. 1950s.
Wolfgang Pauli (1900-1958) - an Austrian theoretical theorist, known as one of the pioneers of quantum physics. He won the 1945 Nobel Prize in Physics for discovering a new law of nature – the exclusion principle (aka the Pauli principle) and developing spin theory.
Max Planck (1858-1947) - a German theoretical physicist who won the 1918 Nobel Prize in Physics for energy quanta. He was the originator of quantum theory, the physics of atomic and subatomic processes.
Rank 2.5
Lev Landau. 1962.
Rank 2.5 is where Landau initially ranked himself, rather modestly, thinking he didn't produce any foundational accomplishments. He later moved his prominence, as his achievement mounted, to the higher 1.5.
