New Method To Cool Down Antimatter Using Lasers Proposed

Researchers have proposed using lasers to cool down highly energetic anti-hydrogen atoms to better study its properties.

Antimatter is matter that carries an opposite charge and spin. An electron's antimatter counterpart is the positron. The electron is negatively charged while the positron is positively charged. The antimatter counterpart of a positively charged proton is a negative charge antiproton.

When antimatter collides with matter, they destroy each other and release energy in a process called annihilation. It must be noted that despite having opposite charges and quantum spin, both particles still carry positive energy.

In 1929, Dmitri Skobeltsyn and Chung-Yao Chao were the first to observe positrons in separate experiments. They noted that the observed particles behaved like electrons but curved in the opposite direction in an applied magnetic field. Neither scientists pursued the anomaly.

It was in 1932, that the positron was officially discovered by Carl D. Anderson, who also coined the term "positron". He was awarded the Nobel Prize for Physics in 1936 for the discovery.

In 1995, physicists at CERN for the first time produced nine anti-hydrogen atoms. This was done by combining one positron and one antiproton. This was followed up by Fermilab which produced 100 antihydrogen atoms.

The resulting antihydrogen atoms proved to be too energetic or "hot" for it to be observed and studied carefully. Subsequent experiments like CERN's Antiproton Decelerator in 1999 managed to lower its energy levels but was still difficult to study.

In 2005, CERN formed the ALPHA collaboration (Antihydrogen laser physics apparatus) whose primary goal is to create less energetic ("cold") antihydrogen atoms that are better suited to study

Physicists Cool OH Molecules To Near Absolute Zero Through Evaporative Cooling

Researchers have created a process that can cool molecules to near absolute zero temperatures through evaporative cooling. Previous processes were then limited to ultra-cooling atoms.

Ultra cold atom physics deals with atoms that are at a temperature close to absolute 0 or 0 K (kelvins). In this field of science, temperature is measured at the nanoscale or at nano-kelvins (nK).

JILA researchers developed a new magnetic trap and a new technique to achieve "evaporative cooling" of hydroxyl molecules (one hydrogen atom bonded to one oxygen atom). A microwave pulse at a specific frequency converts hot molecules inside the trap to a slightly different energy state. A small electric field is pulsed on briefly to destabilize and eject these converted molecules from the trap. As the microwave frequency is slowly altered, molecules distributed inside the trap (which has a varied magnetic field strength) are progressively converted and removed from the top of the trap, where molecules are hotter, to the bottom, where molecules are cooler.
Credit: Baxley and Ye Group/JILA

Since it is impossible to bring an object to absolute zero (as stated in the Third Law of Thermodynamics), ultracold atom physics study objects that are close to absolute zero. The coldest an atom has been brought down to is 0.45 nK (nano kelvin) or 4.5 x 10^-10 K or 0.00000000045 K.

At these levels, atoms start to behave differently and their properties start to move from classical physics to quantum mechanics.

A property that scientists are interested in is the transformation of atoms into a new form of matter called the Bose-Einstein Condensate (BEC). The Bose-Einstein condensate happens when atoms that are brought down to near absolute zero start to behave like waves rather than particles.

As the temperature goes down, these atoms start to vibrate in the same wavelength. Because of this, they start to behave like a single mass object, the Bose-Einstein condensate.

Laser cooling and evaporative cooling are the two ways that scientists use to lower the temperature of atoms. Laser cooling in simple terms uses laser light on atoms to manipulate photons to lowers the energy level of the atom

With evaporative cooling, atoms with higher energy levels (temperature) are ejected out of an optical or magnetic trap until only atoms with the lowest energy levels are left. BECs and ultracold atoms are at very low temperatures are highly sensitive to heat (2nd Law of Thermodynamics).

Practical applications of ultracold atom physics range from super sensitive sensors to atom chips used in diodes and semiconductors. Current technologies used by magnetic levitation (mag-lev) trains, quantum computers and MRI devices utilize principles behind ultracold atom physics.

Ultra Cold Atom Physics Experiment Delves Deep Into Bose-Einstein Condensates

Ultra cold atomic physics is a field of quantum mechanics. It deals with the observation and experimentation of atoms that are brought down to a temperature close to absolute zero.

To cool down these atoms, scientist uses two techiques, laser cooling and evaporative cooling. Atoms in an optical or magnetic trap are subjected to the cooling process and the hotter atoms are ejected from the trap leaving in the ultra cooled atoms.

Since it is impossible to lower the temperature of an object to absolute zero (as stated in the 3rd law of thermodynamics), atoms are cooled down as close to absolute zero as possible (1 nanokelvin). In 2003, MIT Researchers achieved the lowest temperature which is .45 nK (nano kelvin) or 4.5 x 10-10 K or 0.00000000045 K.

A fundamental principle of cold atom physics is the Bose-Einstein Condensate. This is a property of ultra cold atoms where they merge together and form a new form of matter. The underlying principle here is that when subject to ultra low temperatures, atom which behaves as particles, will start to manifest more wave-like properties. Ultimately, all other surrounding atoms will start to vibrate at the same frequency or have the same wavelength, forming one single mass - the Bose-Einstein Condensate.

Cold atom physicsand quantum mechanics have lots to offer in real world applications. Mag-Lev (Magnetic levitation) trains, quantum computers, and even Magnetic Resonance Imaging (MRI) use its basic principles.

Experiment in University of Florida laboratory corrects prediction in quantum theory

An international team of scientists is rewriting a page from the quantum physics rulebook using a University of Florida laboratory once dubbed the coldest spot in the universe.

Much of what we know about quantum mechanics is theoretical and tested via computer modeling because quantum systems, like electrons whizzing around the nucleus of an atom, are difficult to pin down for observation. One can, however, slow particles down and catch them in the quantum act by subjecting them to extremely cold temperatures. New research, published in the Sept. 20 edition of the journal Nature, describes how this freeze-frame approach was recently used to overturn an accepted rule of thumb in quantum theory.

"We are in the age of quantum mechanics," said Neil Sullivan, a UF physics professor and director of the National High Magnetic Field Laboratory High B/T Facility on the UF campus -- home of the Microkelvin lab where experiments can be conducted in near-absolute zero temperatures. "If you've had an MRI, you have made use of a quantum technology."

The magnet that powers an MRI scanner is a superconducting coil transformed into a quantum state by very cold liquid helium. Inside the coil, electric current flows friction free.

Quantum Effects in Cold Atom Physics Through Pre-Thermalization Are More Than Expected

On an atom chip (top), clouds of ultracold atoms (red) are created. They are allowed to interfere, creating an ordered matter-wave interference pattern (bottom).
Credit: Vienna University of Technology

Absolute zero is measured at 0 kelvins. The 3rd law of thermodynamics dictate that it is impossible to cool down an object to exactly 0 kelvins. Since cold is the absence of heat, absolute zero would mean that there is no heat left in the object or system. In 2003, MIT Researchers achieved the lowest temperature which is .45 nK (nano kelvin) or 4.5 x 10-10 K or 0.00000000045 K.

Ultracold atoms are atoms that are maintained at temperatures close to absolute zero. The study that uses ultracold atoms in relation to fundamental quantum phenomena is called Cold Atom Physics. Applications for this technology range from quantum computers, and quantum simulators to ultra-high-precision atomic clocks and quantum metrology.

One of the basic underlying phenomenon of cold atom physics is the Boss-Einstein Condensate (BEC). This is a new state of mater that forms in very low temperatures. When atoms are cooled down to very low temperatures, they start to behave in wave like properties, as the temperature keeps going down, they start to merge and behave like one singular wave like particle. This was predicted by Satyendra Nath Bose and Albert Einstein in 1924–25 and was successfully produced and observed in 1995.

Ultracold atoms reveal surprising new quantum effects

Every day we observe systems thermalizing: Ice cubes in a pot of hot water will melt and will never remain stable. The molecules of the ice and the molecules of the water will reach thermal equilibrium, ending up at the same temperature. Well-ordered ice crystals turn into a disordered liquid.

Experiments at the Vienna Center for Quantum Science and Technology (VCQ) at the Vienna University of Technology have shown that in the quantum world the transition to thermal equilibrium is more interesting and more complicated than assumed so far.