photons attraction?

Question

so: when they move, photons have a small mass m=E/c^2, so undetectable gravity has an effect on them
then if you get together lots of photons, the gravity that acts upon them, can we create a material, like a gas or a liquid or a crystal?

Answer 1

In modern physics, the photon is the elementary particle responsible for electromagnetic phenomena. It mediates electromagnetic interactions and makes up all forms of light. The photon has zero invariant mass and travels at the constant speed c, the speed of light in empty space. However, in the presence of matter, a photon can be absorbed, transferring energy and momentum proportional to its frequency. Like all quanta, the photon has both wave and particle properties, exhibiting wave–particle duality.

The modern concept of the photon was developed gradually (1905–17) by Albert Einstein to explain experimental observations that did not fit the classical wave model of light. In particular, the photon model accounted for the frequency dependence of light's energy, and explained the ability of matter and radiation to be in thermal equilibrium. Other physicists sought to explain these anomalous observations by semiclassical models, in which light is still described by Maxwell's equations but the material objects that emit and absorb light are quantized. Although these semiclassical models contributed to the development of quantum mechanics, further experiments proved Einstein's hypothesis that light itself is quantized; the quanta of light are photons.

The photon concept has led to momentous advances in experimental and theoretical physics, such as lasers, Bose–Einstein condensation, quantum field theory, and the probabilistic interpretation of quantum mechanics. According to the Standard Model of particle physics, photons are responsible for producing all electric and magnetic fields, and are themselves the product of requiring that physical laws have a certain symmetry at every point in spacetime. The intrinsic properties of photons — such as charge, mass and spin — are determined by the properties of this gauge symmetry. Photons have many applications in technology such as photochemistry, high-resolution microscopy, and measurements of molecular distances. Recently, photons have been studied as elements of quantum computers and for sophisticated applications in optical communication such as quantum cryptography.


The photon is massless,has no electric charge and does not decay spontaneously in empty space. A photon has two possible polarization states and is described by three continuous parameters: the components of its wave vector, which determine its wavelength and its direction of propagation. Photons are emitted in many natural processes, e.g., when a charge is accelerated, when an atom or a nucleus jumps from a higher to lower energy level, or when a particle and its antiparticle are annihilated. Photons are absorbed in the time-reversed processes which correspond to those mentioned above: for example, in the production of particle–antiparticle pairs or in atomic or nuclear transitions to a higher energy level.

Since the photon is massless, the photon moves at (the speed of light in empty space) and its energy and momentum are related by , where is the magnitude of the momentum. For comparison, the corresponding equation for particles with an invariant mass would be , as shown in special relativity.

The energy and momentum of a photon depend only on its frequency or, equivalently, its wavelength



and consequently the magnitude of the momentum is


where (known as Dirac's constant or Planck's reduced constant); is the wave vector (with the wave number as its magnitude) and is the angular frequency. Notice that points in the direction of the photon's propagation. The photon also carries spin angular momentum that does not depend on its frequency. The magnitude of its spin is and the component measured along its direction of motion, its helicity, must be . These two possible helicities correspond to the two possible circular polarization states of the photon (right-handed and left-handed).

To illustrate the significance of these formulae, the annihilation of a particle with its antiparticle must result in the creation of at least two photons for the following reason. In the center of mass frame, the colliding antiparticles have no net momentum, whereas a single photon always has momentum. Hence, conservation of momentum requires that at least two photons are created, with zero net momentum. The energy of the two photons — or, equivalently, their frequency — may be determined from conservation of four-momentum. The reverse process, pair production, is the dominant mechanism by which high-energy photons such as gamma rays lose energy while passing through matter.

The classical formulae for the energy and momentum of electromagnetic radiation can be re-expressed in terms of photon events. For example, the pressure of electromagnetic radiation on an object derives from the transfer of photon momentum per unit time and unit area to that object, since pressure is force per unit area and force is the change in momentum per unit time.

Answer 2

at certain energies, photons can also create mass by creating of pairs electron-positron, but i don't know if the gravity between photons is strong enough to create a gas at least and don't know how to increase it other than adding more photons

but you can calculate the gravity between 2 photons starting with their masses at a certain frequency and after that calculating how many photons you need to create a gas, let's say

also the temperature at which is stable, have no idea how to calculate it

Answer 3

When electrons "orbiting" a nucleus of an atom get energized, they enter higher states of energy, upon falling back to lower energy states, they release this energy in the form of photons, an electromagnetic wave of a specific frequency, and therefore a specific energy. It also occurs during radioactive decay, where "unstable" nuclei emit electrons as radiation. The explanation for these phenomenon lies in a field of physics known as quantum mechanics, where many fascinating things about the fundamental forces (strong and weak force) which govern the nature and behavior of atomic and subatomic particles, their energy transformations and release of energy can be found

Answer 4

Photons have no mass so gravity doesn't affect them.