I know Julia from an orientation phase between high school and university. Sadly we lost contact for several years and just met again last year at an anniversary event. Shortly after our meeting Julia started working on her current project, so I could watch the project grow: Every Sunday a new colored origami object. 

I have a history with origami myself. Towards the end of my Master's in mathematics my dedication to origami was particularly strong, because I Feld a desire for something tangible to balance the abstractness of my studies. The regular patterns in Julia's origami objects remind me in my favorite folding technique, which turns regular folding patterns by overlaps and twists to complex creations like a fish with scales, a bird with feathers, floral or abstract patterns. 

A special feature of her origami works is that Julia does not use colored paper, but first folds white paper and afterwards colors the resulting surfaces herself, following a certain principle for the choice of colors. 

When she moved from two-colored to three-colored objects I saw a connection to my professional interest: hadron physics. 

Hadrons are tiny composite particles, which are bound due to the strong interaction. In the simplest case they consist of a quark and an antiquark, of three quarks or of three antiquarks. Protons and neutrons for example consist of three quarks in that model. These objects are observed to follow certain rules which are depicted by assigning one of the colors red, green or blue to each quark and antired, antigreen or antiblue to each antiquark: To compose a hadron the colors of the quarks and antiquarks must combine to white. The corresponding specialist term is color charge. The principle and choice of these colors is also used to create colors on a monitor. 

In a color circle these three colors must have the same distance from each other while the corresponding anticolors must lie in the opposite sides. Besides that, any choice of colors other than red, green and blue would be valid, too. 

I believe that artistic and playful examination of the known physical principles can inspire scientists and lead to new insights. 

(Dr. Miriam Kümmel, August 2019)

In physics the colors correspond to wavelengths of light. A rainbow is visible when light shines through the water drops of a rain shower or through a prism, because the light is bend differently according to its wavelength. 

Our perception of color is different. Red and violett are not the ends of a color spectrum via orange, yellow, green and blue, but connected by nuances of purple. Hence the colors from a circle. 

We cannot distinguish between light of a single wavelength or a mixture of light with different wavelengths. Thus, it is possible to create all colors with a printer using only the three color cyan, magenta and yellow. 

Monitors crate the colors by using red, green and blue pixels. If they all are illuminated with same intensity it creates the impression of white light. 

The principle of three different manifestations which balance each other out brought the term color into physics of strong interaction. In the frame of the strong interaction it totally unconnected to the wavelengths of light. The strong interaction causes protons and neutrons to form atomic nuclei, even though the positively charged protons repel each other. 

Artists are also interested in examining the effects that colors have on each other. The works of Julia Neuberger exhibit an analogy to the color combinations which are relevant in the physics of strong interaction. 

Protons and neutrons consist each of a red, a green, and a blue quark, which are bound due to the strong interaction. By means of particle accelerators it is possible to create antiquarks with colors which are called attired, antigen and antiblue. 

Also combinations of a quark and an antiquark with the corresponding anticolor or three antiquarks with three different anticolors are color-neutral and are observed. Until now no single quark has been observed, but only bound quarks in combination, where the colors balance out. 

A quark (or antiquark) may change its color by emitting a gluon, which then carries the original color and the anticolor corresponding to the new color of the quark. Thus, overall the colors are balanced out at all times. A quark can also absorb a gluon which carries the corresponding anti color so that the remaining color of gluon is transferred to the quark. Gluons can also emit or absorb other gluons as long as color and anti color match. It is even possible that a gluon transforms to a quark-antiquark pair, which then have the color and anticolor the gluon had before. Typically the quark and antiquark recombine after a very short time to gluon again. 

These color changes happen all the tome within every proton and neutron. Actually one 2% of the proton mass originate from the constituent quark masses and the remaining 98% are generated by the strong interaction including the above processes. How exactly that works is not yet understood, it is a current topic in physical research to conclude testable predictions from the different hypotheses and provide the experiments to test them. 

The color-neutral quark(-antiquark) combinations created in accelerators decay after a very short time into the usual particles surrounding us. By studying the decays new insights on strong interaction can be retrieved. The PANDA-experiment will contribute significantly to that aim. 

(Dr. Miriam Kümmel, August 2019)