Exotic matter

There are several proposed types ofexotic matter:

• Hypothetical particlesand states of matter that have not yet been encountered, but whose properties would be within the realm of mainstream physics if found to exist.
• Several particles whose existence has been experimentally confirmed that are conjectured to beexotic hadronsand within theStandard Model.
• States of matterthat are not commonly encountered, such asBose–Einstein condensates,fermionic condensates,nuclear matter,quantum spin liquid,string-net liquid,supercritical fluid,color-glass condensate,quark–gluon plasma,Rydberg matter,Rydberg polaron,photonic matter,Wigner crystal,Superfluidandtime crystalbut whose properties are entirely within the realm of mainstream physics.
• Forms of matter that are poorly understood, such asdark matterandmirror matter.
• Ordinary matter that when placed underhigh pressure,may result in dramatic changes in its physical or chemical properties.
• Degenerate matter
• Exotic atoms

Negative mass

Main article:Negative mass

Negative mass would possess some strange properties, such as accelerating in the direction opposite of appliedforce.Despite being inconsistent with the expected behavior of "normal" matter, negative mass is mathematically consistent and introduces no violation ofconservation of momentumorenergy.It is used in certain speculative theories, such as on the construction of artificialwormholesand theAlcubierre drive.The closest known real representative of such exotic matter is the region of pseudo-negative-pressuredensity produced by theCasimir effect.

Complex mass

Main article:Tachyon § Mass

A hypothetical particle with complex rest mass would always travel faster than thespeed of light.Such particles are calledtachyons.There is no confirmed existence of tachyons.

$E={\frac {m\cdot c^{2}}{\sqrt {1-{\frac {\left|\mathbf {v} \right|^{2}}{c^{2}}}}}}$

If the rest mass$m$is complex this implies that the denominator is complex because the total energy isobservableand thus must bereal.Therefore, the quantity under the square root must be negative, which can only happen ifvis greater thanc.As noted byGregory Benfordet al.,special relativityimplies that tachyons, if they existed, could be used to communicate backwards in time(seetachyonic antitelephone). Becausetime travelis considered to be non-physical, tachyons are believed by physicists either not to exist, or else to be incapable of interacting with normal matter.

Inquantum field theory,complex mass would inducetachyon condensation.

Materials at high pressure

At high pressure, materials such assodium chloride(NaCl) in the presence of an excess of either chlorine or sodium were transformed into compounds "forbidden" by classical chemistry, such asNa
₃ClandNaCl
₃.Quantum mechanical calculations predict the possibility of other compounds, such asNaCl
₇,Na
₃Cl
₂andNa
₂Cl.The materials are thermodynamically stable at high pressures. Such compounds may exist in natural environments that exist at high pressure, such as the deep ocean or insideplanetary cores.The materials have potentially useful properties. For instance,Na
₃Clis a two-dimensional metal, made of layers of pure sodium and salt that can conduct electricity. The salt layers act as insulators while the sodium layers act as conductors.

See also

• Antimatter– Material composed of antiparticles of the corresponding particles of ordinary matter
• Dark energy– Energy driving the accelerated expansion of the universe
• Dark matter– Concept in cosmology
• Gravitational interaction of antimatter– Theory of gravity on antimatter
• Mirror matter– Hypothetical counterpart to ordinary matter
• Negative energy– Concept in physics
• Negative mass– Concept in physical models
• QCD matter– Hypothetical phases of matter
• Strange matter– Degenerate matter made from strange quarks

External links

• Exotic Matter and Negative EnergyonYouTube
• The Riddle of AntiMatteronYouTube