In the 20th century, physicists used laser-cooling technology to break the record for the coldest temperature in the universe. This led to new quantum states of matter. 

Here’s some related information: 

• Laser cooling A technique that uses two or more detuned lasers to cool atoms. The lasers ensure that the atom re-emits photons in a direction that opposes its motion. This technique is used to create ultracold atoms. 
• Bose–Einstein condensate A state of matter where separate atoms or subatomic particles coalesce into a single quantum mechanical entity. Einstein proposed that cooling bosonic atoms to a very low temperature would cause them to fall into the lowest accessible quantum state. 
• Examples of Bose-Einstein condensate
  • Superfluid helium-4 
  • Superconducting materials 
  • Lasers 
  • Atomic clocks 
  • Quantum information processing 
  • Cosmology 
  • Neutron stars 
  • Dark matter

Here, low temperatures and high densities force atoms into one of two exotic states of matter: either a Bose–Einstein condensate (BEC), in which all of the atoms in a gas coalesce into the same quantum state, or a degenerate Fermi gas(DFG), in which the total energy of the gas stops decreasing because all the

In 2014, scientists at an Italian institute used lasers to cool a copper vessel to -273.144 degrees Celsius, breaking the record for the lowest temperature ever achieved in the universe. 

Lasers are the most powerful sources of light and can cool atoms to within a millionth of a degree of absolute zero (-273.15° Celsius or zero Kelvin). 

Scientists have also used lasers to chill a dipolar molecule to a temperature just a fraction of a degree above absolute zero. This is an important step in the race to generate new kinds of ultra-cold matter that could be used for everything from quantum computing to chemistry

The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories. In 1975, Hänsch and Schawlow, and independently Wineland and Dehmelt, realized that laser light could potentially be used to cool atoms and ions, respectively. 

In 1985, Steven Chu and his co-workers at the Bell Laboratories in Holmdel, New Jersey, developed a method for cooling atoms with laser light. The method is based on the slowing down effect, which forms the basis for a powerful method of cooling atoms with laser light. 

The essential physics behind laser cooling can be traced back to Albert Einstein’s 1917 observation that photons, the fundamental “particles” of light, must carry momentum, and this momentum can be used to change the motion of atoms.

Laser cooling is important for several reasons: 

• Quantum physics Laser cooling is used to create ultracold atoms for quantum physics experiments. These experiments are performed near absolute zero, where unique quantum effects like Bose–Einstein condensation can be observed. 
• Optical clocks Laser cooling is also a primary tool in optical clock experiments. 
• Quantum information processing Laser cooling of ions in traps can be used for experiments ranging from basic physics tests to quantum information processing applications. 
• Cold atomic beams Laser cooling can be used to produce accurately controlled structures with cold atomic beams. 
• Simulations Ultra-cold atoms can be used to simulate many-body quantum systems, such as materials and magnetic systems. 

Laser cooling works by shining laser light on atoms. The most common types of lasers used for cooling atoms are diode lasers and dye lasers

The basic principle of laser cooling is the absorption and re-emission of photons. When an atom absorbs a photon, its energy increases and it moves to a higher energy level

The basic principle used to cool down atoms is to slow them down. Slowing down an atom lowers its kinetic energy and thermal energy, which will eventually lead to a decrease in its temperature. 

Laser cooling relies on the change in momentum when an object, such as an atom, absorbs and re-emits a photon. 

A simple scheme for laser cooling is Doppler cooling. In Doppler cooling, light forces are exerted by absorption and subsequent spontaneous emission of photons. The rate of these processes depends on the velocity of an atom or ion due to the Doppler shift. 

Laser cooling uses the resonant scattering of laser light by atomic particles. The laser is tuned to the red, or low-frequency side of the atomic “cooling transition”

Doppler cooling is the most common method of laser cooling. It’s often used with a magnetic trapping force to create a magneto-optical trap. Doppler cooling is used to cool low-density gases to the Doppler cooling limit

Other methods of laser cooling include: 

• Optical molasses: This technique can cool neutral atoms to a few microkelvins. It uses three pairs of counter-propagating circularly polarized laser beams that intersect in the region where the atoms are present. 
• Sisyphus cooling: This technique is used to cool charged particles, or ions. It involves a polarization gradient, which is generated by two counter-propagating linearly polarized laser beams with perpendicular polarization directions. 
• Resolved sideband cooling: This is another method of laser cooling. 
• Raman sideband cooling: This is another method of laser cooling. 
• Cavity mediated cooling: This is another method of laser cooling.

In 2010, scientists used lasers to cool a dipolar molecule to a temperature just above absolute zero (around –273 °C). This was a significant step in the development of new types of ultra-cold matter that could be used in chemistry and quantum computing

The technique used to cool the molecules is called laser cooling. It involves hitting the molecules with laser beams from opposite directions to reduce their random velocities. 

The technique is based on the principle that the frequency of light absorbed by an atom depends on its velocity. As an atom moves towards a laser, the frequency of the light it absorbs shifts to a higher value. As it moves away from the laser, the frequency shifts to a lower value

A Bose–Einstein condensate (BEC) is a state of matter that occurs when atoms or subatomic particles are cooled to near absolute zero and coalesce into a single quantum mechanical entity

When cooled to near absolute zero, atoms have almost no free energy to move relative to each other. At this point, the atoms begin to clump together and enter the same energy states. 

In a BEC, all the constituent particles exist in their lowest energy level. The Pauli Exclusion Principle prevents more than one electron per quantum state, but no such limit is imposed on particles known as bosons, such as helium-4 atoms. 

BECs behave in many aspects like a supraliquid with zero viscosity

Here are some ways that Bose–Einstein condensates (BECs) differ from the three states of matter: 

• Superfluid: BECs are superfluid, which means they behave differently from ordinary liquids and gases. For example, superfluids can’t rotate as a rigid body, but instead form quantized line defects called vortices. 
• Interactions: BECs are extremely fragile and can be easily warmed past the condensation threshold by interactions with the external environment. This eliminates their interesting properties and forms a normal gas. 
• Composition: BECs are made up of a gas of bosons at low densities. 
• Quantum state: All the particles in a BEC exist in the same quantum state, so they behave almost as one megaparticle. 
• State of matter: BECs are sometimes referred to as the “fifth state of matter”

(Full article source google)

Best woman clothes on heavy discount on Amazon