The Cold Atom Laboratory (CAL) is an experimental instrument on board the ISS, which launched in 2018. It creates an extremely cold environment in microgravity in order to study behaviour of atoms in these conditions. [1] [2]
The CAL was developed at JPL in Pasadena, California. [3] It was originally scheduled for launch to the International Space Station (ISS) in June 2017. [4] It was then delayed until a scheduled launch on a SpaceX CRS-12 rocket in August 2017. [5] It was finally launched on May 21, 2018. [2] The initial mission had a duration of 12 months with up to five years of extended operation. [4]
In January 2020 it underwent hardware upgrades, which were carried out over an eight-day period by astronauts Christina Koch and Jessica Meir under the supervision of ground controllers. [1] The upgrade included an atom interferometer which can be used to study the equivalence principle. [6]
In July 2021, another upgrade by astronaut Megan McArthur gave CAL the ability to work with ultracold potassium atoms in addition to rubidium atoms. [7]
The instrument creates extremely cold conditions in the microgravity environment of the ISS, leading to the formation of Bose Einstein Condensates (BECs) that are orders of magnitude colder than those that are created in laboratories on Earth. [4] In a space-based laboratory, up to 10 seconds interaction times and as low as 1 picokelvin temperatures are achievable, and it could lead to exploration of unknown quantum mechanical phenomena and test some of the most fundamental laws of physics. [8] [4] These experiments are best done in a freely falling environment, because it is more conducive to uninhibited formation of BECs. Ground based experiments suffer from the effect of the condensate interacting asymmetrically with the apparatus, interfering with the time evolution of the condensate. In orbit, experiments can last much longer because freefall is sustained indefinitely. [4] NASA's JPL scientists state that the CAL investigation could advance knowledge in the development of extremely sensitive quantum detectors, which could be used for monitoring the gravity of Earth and other planetary bodies, or for building advanced navigation devices. [4]
The results of the experiments from 2019 were reported in 2020, demonstrating successful operation of the laboratory. This enables improved research of BECs and quantum mechanics, since physics are scaled to macroscopic scales in BECs. The lab supports long-term investigations of few-body physics, and supports the development of techniques for atom-wave interferometry and atom lasers. [9] [10]
Absolute zero is the lowest limit of the thermodynamic temperature scale; a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as zero kelvin. The fundamental particles of nature have minimum vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. The theoretical temperature is determined by extrapolating the ideal gas law; by international agreement, absolute zero is taken as −273.15 degrees on the Celsius scale, which equals −459.67 degrees on the Fahrenheit scale. The corresponding Kelvin and Rankine temperature scales set their zero points at absolute zero by definition.
In condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero. Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which microscopic quantum mechanical phenomena, particularly wavefunction interference, become apparent macroscopically. More generally, condensation refers to the appearance of macroscopic occupation of one or several states: for example, in BCS theory, a superconductor is a condensate of Cooper pairs. As such, condensation can be associated with phase transition, and the macroscopic occupation of the state is the order parameter.
In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma. Many intermediate states are known to exist, such as liquid crystal, and some states only exist under extreme conditions, such as Bose–Einstein condensates and Fermionic condensates, neutron-degenerate matter, and quark–gluon plasma. For a list of exotic states of matter, see the article List of states of matter.
A fermionic condensate is a superfluid phase formed by fermionic particles at low temperatures. It is closely related to the Bose–Einstein condensate, a superfluid phase formed by bosonic atoms under similar conditions. The earliest recognized fermionic condensate described the state of electrons in a superconductor; the physics of other examples including recent work with fermionic atoms is analogous. The first atomic fermionic condensate was created by a team led by Deborah S. Jin using potassium-40 atoms at the University of Colorado Boulder in 2003.
Deborah Shiu-lan Jin was an American physicist and fellow with the National Institute of Standards and Technology (NIST); Professor Adjunct, Department of Physics at the University of Colorado; and a fellow of the JILA, a NIST joint laboratory with the University of Colorado.
Wolfgang Ketterle is a German physicist and professor of physics at the Massachusetts Institute of Technology (MIT). His research has focused on experiments that trap and cool atoms to temperatures close to absolute zero, and he led one of the first groups to realize Bose–Einstein condensation in these systems in 1995. For this achievement, as well as early fundamental studies of condensates, he was awarded the Nobel Prize in Physics in 2001, together with Eric Allin Cornell and Carl Wieman.
Lene Vestergaard Hau is a Danish physicist and educator. She is the Mallinckrodt Professor of Physics and of Applied Physics at Harvard University.
An atom laser is a coherent state of propagating atoms. They are created out of a Bose–Einstein condensate of atoms that are output coupled using various techniques. Much like an optical laser, an atom laser is a coherent beam that behaves like a wave. There has been some argument that the term "atom laser" is misleading. Indeed, "laser" stands for light amplification by stimulated emission of radiation which is not particularly related to the physical object called an atom laser, and perhaps describes more accurately the Bose–Einstein condensate (BEC). The terminology most widely used in the community today is to distinguish between the BEC, typically obtained by evaporation in a conservative trap, from the atom laser itself, which is a propagating atomic wave obtained by extraction from a previously realized BEC. Some ongoing experimental research tries to obtain directly an atom laser from a "hot" beam of atoms without making a trapped BEC first.
A bosenova or bose supernova is a very small, supernova-like explosion, which can be induced in a Bose–Einstein condensate (BEC) by changing the external magnetic field, so that the "self-scattering" interaction transitions from repulsive to attractive due to the Feshbach resonance, causing the BEC to "collapse and bounce" or "rebound."
In condensed matter physics, an ultracold atom is an atom with a temperature near absolute zero. At such temperatures, an atom's quantum-mechanical properties become important.
In experimental physics, a magnetic trap is an apparatus which uses a magnetic field gradient to trap neutral particles with magnetic moments. Although such traps have been employed for many purposes in physics research, they are best known as the last stage in cooling atoms to achieve Bose–Einstein condensation. The magnetic trap was first proposed by David E. Pritchard.
Joannes Theodorus Maria (Jook) Walraven is a Dutch experimental physicist at the Van der Waals-Zeeman Institute for experimental physics in Amsterdam. From 1967 he studied physics at the University of Amsterdam. Both his doctoral research and PhD research was with Isaac Silvera, on the subject of Bose-Einstein Condensation. Because of the difficulty of his research subject, his promotion took six years instead of four. The aim of his PhD research was to make a gas of atomic hydrogen, which could become the world's first quantum gas. This might then be a suitable candidate for a Bose-Einstein Condensate (BEC).
Bose–Einstein condensation can occur in quasiparticles, particles that are effective descriptions of collective excitations in materials. Some have integer spins and can be expected to obey Bose–Einstein statistics like traditional particles. Conditions for condensation of various quasiparticles have been predicted and observed. The topic continues to be an active field of study.
Anita Sengupta is an American aerospace engineer. She is a graduate in aerospace and mechanical engineering of the Viterbi School of Engineering at the University of Southern California. She was the lead systems engineer of the team that developed the parachute system that was deployed during the landing of Mars Science Laboratory Curiosity. She was subsequently the project manager of the Cold Atom Laboratory at the Jet Propulsion Laboratory at Caltech. She was then the Senior Vice President of Systems Engineering at Virgin Hyperloop One. She is currently Chief Product Officer at Airspace Experience Technologies (ASX).
Sandro Stringari is an Italian theoretical physicist, who has contributed to the theory of quantum many-body physics, including atomic nuclei, quantum liquids and ultra-cold atomic Bose and Fermi gases. He has developed in a systematic way the sum rule approach to the collective behavior of interacting systems.
National Laboratory of Atomic, Molecular and Optical Physics is the national inter-university research center with the headquarters at Institute of Physics of Nicolaus Copernicus University in Toruń, Poland. Established in 2002, the Laboratory is focused on atomic, molecular, and optical physics (AMO).
Bose–Einstein condensation of polaritons is a growing field in semiconductor optics research, which exhibits spontaneous coherence similar to a laser, but through a different mechanism. A continuous transition from polariton condensation to lasing can be made similar to that of the crossover from a Bose–Einstein condensate to a BCS state in the context of Fermi gases. Polariton condensation is sometimes called “lasing without inversion”.
The I. I. Rabi Prize in Atomic, Molecular, and Optical Physics is given by the American Physical Society to recognize outstanding work by mid-career researchers in the field of atomic, molecular, and optical physics. The award was endowed in 1989 in honor of the physicist I. I. Rabi and has been awarded biannually since 1991.
Gretchen K. Campbell is an American atomic, molecular, and optical physicist associated with the National Institute of Standards and Technology. She works in the field of atomtronics and has received awards in recognition of her research contributions on Bose-Einstein condensates.