# States of matter

Dr. S. S. VERMA; Department of Physics, S.L.I.E.T., Longowal; Distt.-Sangrur (Punjab)-148 106

2020-06-02 17:37:05

Credit: pixabay.com

In physics, a state of matter is one of the distinct forms in which matter can exist. States of matter are distinguished by changes within the properties of matter associated with external factors like pressure and temperature. States are usually distinguished by a discontinuity in one amongst those properties. Generally speaking, any form of matter with special characteristics is designated to be a form or state only when it exists in abundance naturally. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma. All these states of matter have their own distinguished and specific properties.

1. Low-energy states of matter

Matter at low energy generally exists in its classical states (solid, liquid and gas) and their other forms like:

Amorphous solid: A solid in which there is no far-range order of the positions of the atoms.

Crystalline solid: A solid in which atoms, molecules, or ions are packed in regular order.

Plastic crystal: A molecular solid with long-range positional order but with constituent molecules retaining rotational freedom.

Quasi-crystal: A solid in which the positions of the atoms have long-range order, but is not in a repeating pattern.

Liquid crystal: Properties intermediate between liquids and crystals. Generally, able to flow like a liquid but exhibiting long-range order.

Disordered hyper uniformity: A state similar to a liquid and a crystal in properties. Like a crystal, its particles over large distances exhibit uniform density and are unable to compress. Like a liquid, its particles at smaller distances display the same physical properties in all directions.

Non-Newtonian fluid: a fluid that does not follow Newton's law of viscosity.

1. Moderate energy states of matter

Super critical fluid: At sufficiently high temperatures and pressures the distinction between liquid and gas disappears.

Excitation: the application of energy to a particle, object, or physical system.

Degenerate matter: The particles identified in the BEC came to be known as "bosons" and are now seen as a fundamental part of matter. But there's another type of quantum particle: fermions, which are named after Italian physicist Enrico Fermi. Because of how they spin, fermions cannot occupy the same quantum state within a quantum system at the same time. The highly compressed state of matter which often exists in the cores of massive stars. The core’s gas is super compressed and the primary source of pressure is no longer thermal, but quantum. The matter under very high pressure, supported by the Pauli Exclusion Principle can have two states i) Electron-degenerate matter- found inside white dwarf stars. Electrons remain bound to atoms but are able to transfer to adjacent atoms and ii) Neutron-degenerate matter- found in neutron stars. Vast gravitational pressure compresses atoms so strongly that the electrons are forced to combine with protons via inverse beta-decay, resulting in a super dense conglomeration of neutrons.

Strange matter: Types of quark matter that may exist inside some neutron stars close to the Tolman–Oppenheimer–Volkoff limit (approximately 2–3 solar masses). May be stable at lower energy states once formed.

Photogenic matter: Inside a quantum nonlinear medium, photons can behave as if they had mass, and can interact with each other, forming photogenic "molecules".

1. Very high energy states

Quark–gluon plasma: A phase in which quarks become free and able to move independently (rather than being perpetually bound into particles, or bound to each other in a quantum lock where exerting force adds energy and eventually solidifies into another quark) in a sea of gluons (subatomic particles that transmit the strong forcethat binds quarks together). May be briefly attainable in particle accelerators, or possibly inside neutron stars.  For up to 10−36 seconds after the Big Bang, the energy density of the universe was so high that the four forces of nature–strong, weak, electromagnetic, and gravitational– are thought to have been unified into one single force. Quark-gluon plasma (QGP) only existed naturally for a few millionths of a second after the Big Bang. During that incredibly small period of time, the universe consisted entirely of a soup of quarks (theoretical subatomic particles carrying a fractional electric charge) and gluons, which "glue" quarks together. Then, the universe began to cool, and the QGP turned into protons and neutrons, which turned into everything in existence.

Quantum states: A state that gives rise to quantize Hall voltage measured in the direction perpendicular to the current flow.

Quantum spin Hall state: a theoretical phase that may pave the way for the development of electronic devices that dissipate less energy and generate less heat. This is a derivation of the quantum Hall state of matter.

Bose–Einstein condensate: a state of matter that occurs very close to absolute zero. At this extremely low temperature, molecular motion almost stops and atoms begin to clump together. Indian physicist Satyendra Nath Bose and Albert Einstein predicted the existence of such a state in the 1920s, but it was not observed until 1995 by Eric Cornell and Carl Wieman. In 1995, scientists created a new state called ‘Bose-Einstein condensate’ by cooling gas to within a few degrees of absolute zero (-273°C), at which point molecular motion almost stops and the atoms behave en masse like a single atom. It is a phase in which a large number of bosons all inhabit the same quantum state, in effect becoming one single wave/particle. This is a low energy phase that can only be formed in laboratory conditions and in very cold temperatures.

Fermionic condensate: Similar to the Bose-Einstein condensate but composed of fermions, also known as Fermi-Dirac condensate. The Pauli Exclusion Principle prevents fermions from entering the same quantum state, but a pair of fermions can behave like a boson, and multiple such pairs can then enter the same quantum state without restriction.

Superconductivity: is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. Superconductivity is the ground state of many elemental metals.

Superfluid: A phase achieved by a few cryogenic liquids at extreme temperature where they become able to flow without friction. A super fluid can flow up the side of an open container and down the outside. Placing a superfluid in a spinning container will result in quantized vortices.

Supersolid: similar to a superfluid, a supersolid is able to move without friction but retains a rigid shape.

Quantum spin liquid: A disordered state in a system of interacting quantum spins which preserves its disorder to very low temperatures, unlike other disordered states.

Heavy fermion materials: Heavy fermion materials or strongly correlated Fermi systems form a new state of matter that defines by quantum phase transitions, and exhibits a universal scaling behavior of its thermodynamic, transport and relaxation properties. Quantum spin liquid, quasicrystals, 2D Fermi liquids, heavy-fermion metals and heavy-fermion superconductors can belong to the new state of matter.

String-net liquid: Atoms in this state have apparently unstable arrangement, like a liquid, but are still consistent in overall pattern, like a solid.

Dropleton: An artificial quasiparticle, constituting a collection of electrons and places without them inside a semiconductor. Dropleton is the first known quasiparticle that behaves like a liquid.

Jahn–Teller metal: A solid that exhibits many of the characteristics of an insulator, but acts as a conductor due to a distorted crystalline structure, however, the experiment was not reproduced and confirmed by other scientists.

Time crystals: A state of matter where an object can have movement even at their lowest energy state.

Rydberg polaron: A state of matter that can only exist at ultra-cool temperatures and consists of atoms inside of atoms.