Richard Feynman later gave an independent systematic derivation of these diagrams from a particle formalism, and they are now called Feynman diagrams.

For example, John Baez has shown a link between Feynman diagrams in Physics and monoidal categories.

In quantum electrodynamics, electromagnetic interactions between charged particles can be calculated using the method of Feynman diagrams, in which we picture messenger particles called virtual photons being exchanged between charged particles.

Dyson was the first person ( besides Feynman ) to appreciate the power of Feynman diagrams, and his 1949 paper ( written in 1948 ) was the first paper using them.

He said in that paper that Feynman diagrams were not just a computational tool, but a physical theory.

Feynman diagrams are pictorial representations of the mathematical expressions governing the behavior of subatomic particles.

The interaction of sub-atomic particles can be complex and difficult to understand intuitively, and the Feynman diagrams allow for a simple visualization of what would otherwise be a rather arcane and abstract formula.

As David Kaiser writes, " since the middle of the 20th century, theoretical physicists have increasingly turned to this tool to help them undertake critical calculations ," and as such " Feynman diagrams have revolutionized nearly every aspect of theoretical physics ".

These integrals do, however, have a regular structure, and may be represented graphically as Feynman diagrams.

The Dyson series can be alternately rewritten as a sum over Feynman diagrams, where at each interaction vertex both the energy and momentum are conserved, but where the length of the energy momentum four vector is not equal to the mass.

In addition to their value as a mathematical tool, Feynman diagrams provide deep physical insight into the nature of particle interactions.

After renormalization, calculations using Feynman diagrams match experimental results with very high accuracy.

Murray Gell-Mann always referred to Feynman diagrams as Stueckelberg diagrams, after a Swiss physicist, Ernst Stueckelberg, who devised a similar notation many years earlier.

However, in 2006 Dyson himself confirmed that the diagrams should be called Feynman diagrams because " he taught us how to use them ".

In their presentations of fundamental interactions, written from the particle physics perspective, Gerard ’ t Hooft and Martinus Veltman gave good arguments for taking the original, non-regularized Feynman diagrams as the most succinct representation of our present knowledge about the physics of quantum scattering of fundamental particles.

In quantum field theories the Feynman diagrams are obtained from Lagrangian by Feynman Rules.

Feynman diagrams are a pictorial representation of a contribution to the total amplitude for a process which can happen in several different ways.

In a non-relativistic theory, there are no antiparticles and there is no doubling, so each Feynman diagram includes only one term.

Feynman diagram and path integral methods are also used in statistical mechanics.

Their motivations are consistent with the convictions of James Daniel Bjorken and Sidney Drell: ” The Feynman graphs and rules of calculation summarize quantum field theory in a form in close contact with the experimental numbers one wants to understand.

Some modification of the Feynman rules of calculation may well outlive the elaborate mathematical structure of local canonical quantum field theory ...” So far there are no opposing opinions.

Feynman diagrams are often confused with spacetime diagrams and bubble chamber images because they all describe particle scattering.

Feynman diagrams are graphs that represent the trajectories of particles in intermediate stages of a scattering process.

They are represented in Feynman diagrams as follows:

The diagrams are drawn according to the Feynman rules which depend upon the interaction Lagrangian.

In Toumey's 2008 article, " Reading Feynman into Nanotechnology ", he found 11 versions of the publication of “ Plenty of Room ", plus two instances of a closely related talk by Feynman, “ Infinitesimal Machinery ,” which Feynman called “ Plenty of Room, Revisited .” Also in Toumey ’ s references are videotapes of that second talk.

Richard Feynman argued that high energy experiments showed quarks are real particles: he called them partons ( since they were parts of hadrons ).

Feynman diagrams | Feynman diagram elementsThese actions are represented in a form of visual shorthand by the three basic elements of Feynman diagrams: a wavy line for the photon, a straight line for the electron and a junction of two straight lines and a wavy one for a vertex representing emission or absorption of a photon by an electron.

( These must not be confused with the arrows of Feynman diagrams which are actually simplified representations in two dimensions of a relationship between points in three dimensions of space and one of time.

These are called Feynman propagators.

Toumey found that the published versions of Feynman ’ s talk had a negligible influence in the twenty years after it was first published, as measured by citations in the scientific literature, and not much more influence in the decade after the Scanning Tunneling Microscope was invented in 1981.

Changes in renormalization scale will simply affect how much of a result comes from Feynman diagrams without loops, and how much comes from the leftover finite parts of loop diagrams.

However, Richard Feynman showed in his famous lectures that the gravitational constant most likely could not have changed this much in the past 4 billion years based on geological and solar system observations ( although this may depend on assumptions about the constant not changing other constants ).

Feynman developed the original idea of his friend into a successful invention, allowing his employer ( and friend ) to keep commercial promises he had made but could not have fulfilled otherwise.

Feynman considered the possibility of direct manipulation of individual atoms as a more powerful form of synthetic chemistry than those used at the time.

The basic rule is that if we have the probability amplitude for a given complex process involving more than one electron, then when we include ( as we always must ) the complementary Feynman diagram in which we just exchange two electron events, the resulting amplitude is the reverse – the negative – of the first.

Feynman diagrams with more than one loop always contain internal boson propagators.

His style of investigating with his own direct methods rather than following the commission schedule put him at odds with Rogers, who once commented, " Feynman is becoming a real pain.

Feynman incredulously explains the magnitude of this error: a " safety factor " refers to the practice of building an object to be capable of withstanding more force than it will conceivably be subjected.

Feynman's suspicions were corroborated by General Kutyna, also on the commission, who cunningly provided Feynman with a broad hint by asking about the effect of cold on O-ring seals after mentioning that the temperature on the day of the launch was far lower than had been the case with previous launches: below freezing at 28 or 29 Fahrenheit (− 2. 2 to − 1. 6 ° C ); previously, the coldest launch had been at 53 ° F ( 12 ° C ).

Feynman did the first quantitative analysis of the device in 1962 using the Maxwell-Boltzmann distribution, showing that if the temperature of the paddle T < sub > 1 </ sub > was greater than the temperature of the ratchet T < sub > 2 </ sub >, it would function as a heat engine, but if T < sub > 1 </ sub > = T < sub > 2 </ sub > there would be no net motion of the paddle.

Magnasco and Stolovitzky ( 1998 ) extended this analysis to consider the full ratchet device, and showed that the power output of the device is far smaller than the Carnot efficiency claimed by Feynman.

Thus, we see that the Feynman amplitude for this graph is nothing more than

In the latter case, the quantum corrections have to vanish at the one and two loop level Feynman diagrams, otherwise the predicted value of the kinetic mixing parameter would be larger than experimentally allowed.

* In 1959, Richard Feynman bet $ 1, 000 ( equivalent to about $ in present day terms ) that no-one could construct a motor no bigger than 1 / 64 of an inch on a side.

In essence, Feynman is saying that for dense materials the polarization of a material is proportional to its electric field, but that it has a different constant of proportionality than for that of a gas.

To quote Richard Feynman "... there is also an amplitude for light to go faster ( or slower ) than the conventional speed of light.