Many people do not believe in the concept of negative energy. However, scientific tests have indicated the presence of negative energy. The concept of negative energy emerged from "Heisenberg’s Uncertainty Principle". Some scientists believe that, negative energy can be used to destroy black holes or to make perpetual-motion machines, build wormholes. Negative enrgy should not be confused with antimatter as these are two separate things. Antimatter is supposed to have positive energy whereas if it had negative energy the result would be zero energy which is not the case with antimatter.
Matter is described as something that occupies space and has mass and includes all atoms and particles that have mass. Everything around including us is made of Matter. Most of the scientific researches and technologies are based on matter. Matter on earth is in solid, liquid and gas eous form and interacts with all the natural forces namely: electromagnetism, gravity and atomic forces.
Matter is made of atoms which consists of mostly electrons, protons and neutrons and particles such as muons, tau, muon neutrino existed after the big bang and now are found only in cosmic radiation. So Antimatter is something that is the opposite of matter which means an electron's (which is -ve charge)antimatter would be an elctron with positive charge called a positron. A proton (+ve charge) antimatter would be a proton with negative charge and similarly neutrons and antineutrons. Reasearch at CERN is being done to create antimatter. It is not sure whether these exist or if they perished right after matter was created. Since matter and antimatter interaction will only result in annihilation, it is thought that even if they exist they might be very far away in the universe.
Most of the matter in the universe is considered to be dark and makes us wonder if it exists at all. The presence of Dark matter is concluded indirectly by measuring other aspects such as motion of stellar objects such as galaxies. When velocities of these galaxies are done and measured, in order for the objects not fly apart there has to be enough mass for the gravity that is balancing or keeping it from falling apart. This inferred mass is therefore consdiered to be present in higher quantities than what is visible to the eye. Hence it is has been concluded that there is dark matter in the universe. It only interacts with electromagnetic forces and weak atomic forces. These forces hold neutrons and protons together inside the nucleus of an atom. Dark matter does not interact with gravity or strong atomic forces.
The concept of negative matter is hypothetical. If negative matter exists, then it is suppose to have negative mass and negative energy. As a result, it should repel normal matter. One should not confuse negative energy with the energy associated with other atomic particles. In physics, there is no such thing as negative matter or mass. Negative energy is not any antimatter mentioned in science journals and thrillers. Antimatter does not have negative mass. For example: The positron closely resembles an electron. However, the positron has a positive charge and the electron has a negative one. Both of them have identical mass and spin. If antimatter had negative energy, it would have demonstrated zero-energy states. Negative energy is not linked to cosmological constant. In inflationary models of the universe, the cosmological constant was postulated. The cosmological constant represents negative pressure but positive energy. Then does negative energy mean less than nothing? Quantum physics states that a region of space can contain less than nothing. The energy per unit volume (energy density) can become less than zero. According to Einstein’s theory of gravity, the integration of energy and matter deforms the geometric fabric of space and time. When negative energy bends space-time, astounding phenomena might occur such as traversable wormholes (tunnels for traveling between the stars), warp drive (propulsion system) and time machines.
In the year 1988, Richard E. Slusher and Bernard Yurke tried an experiment where laser beams were passed through nonlinear optic materials. As a result, photons were produced. These photons alternately enhanced and suppressed the vacuum fluctuations. This created negative energy. In the year 1948, renowned physicist Hendrik B.G. Casimir introduced geometric boundaries into a space. He used two uncharged metal plates to change the vacuum fluctuations. The energy density was calculated to be negative between the two plates. This so-called squeezed vacuum state involves negative energy.