List of unsolved problems in physics

Some of the most important unsolved problems of physics are of a theoretical nature, ie that the existing theories are unable to explain a specific, observed phenomenon or the result of an experiment. The others are experimental in nature, meaning that it is difficult to create an experiment to test a particular theory or to explore a particular phenomenon with greater accuracy.

2.1 Theory of Quantum Gravity
2.2 Vacuum disaster
2.3 Black holes and singularities
2.4 Additional dimensions
2.5 location
2.6 presumption to protect the order of time

3.1 Higgs mechanism
3.2 Hierarchy Problem
3.3 Magnetic monopole
3.4 proton
3.5 Supersymmetry
3.6 generation
3.7 Spontaneous symmetry breaking
3.8 Neutrino
3.9 confinement
3:10 Strong CP Problem
3:11 anomalous magnetic moment

4.1 accretion disk
4.2 solar corona
4.3 Supermassive black holes
4.4 UHECR
4.5 Miscellaneous

5.1 quantum
5.2 atomic nuclei and nuclear astrophysics

6.1 hydrogen / helium
6.2 Myonischer hydrogen

7.1 High-temperature superconductors
7.2 Amorphous materials
7.3 sonoluminescence
7.4 turbulence
7.5 Miscellaneous

Cosmology and General Relativity

Cosmology deals with the origin, evolution and the basic structure of the universe ( cosmos ) as a whole and is a branch of astronomy, which is closely related to astrophysics.

The general relativity theory (ART) describes the interaction between matter (including fields) on the one hand and space and time on the other. She points gravity as a geometric property of the curved four-dimensional space-time. The mathematical description of space-time and its curvature is using the methods of differential geometry.

The standard model of cosmology ( SdK ) based inter alia on the following assumptions:

The validity of the cosmological principle, that is, it is the isotropy and homogeneity of the cosmos
The validity of the general theory of relativity

The standard model is supported by the following observational results:

The Hubble expansion
The cosmic microwave background radiation
The primordial nucleosynthesis, that is, the emergence of the first elements

However, the standard model has the following problems and open questions:

The horizon problem
Exotic particles such as magnetic monopoles
To understand inhomogeneities, which are necessary the current structures of the cosmos
Baryon asymmetry
Dark Matter
Dark Energy
At time t = 0 there is an unrecoverable singularity.

Cosmological inflation

As cosmological inflation is an episode of extremely rapid expansion of the universe is called. Depending on the underlying assumptions they began between 10-43 s, ie the Planck time (or the beginning of the Big Bang itself), and 10-35 s and lasted until a date between 10-33 s and 10-30 s. according to the Big Bang

Is the theory of cosmological inflation correct, and if so, what are the exact details of this period?

What is it hypothetically postulated Inflatonfeld that causes this inflation? If inflation is done at a particular point in space, then it is self-sustaining through inflation of quantum fluctuations ( vacuum fluctuations ), and therefore they may go further in distant regions of the universe?

By adopting an inflationary exponential expansion, the following two open questions of the standard model of cosmology can be answered:

The horizon problem: During the very short period of inflation, the space-time expands faster than light signals, so that today the observer accessible space is causally connected.
The flat universe: inflation " flattens " the curvature of the universe further and further, until eventually a Euclidean space has emerged.

But the following points speak against inflation model:

Poor inflation or no inflation: Bad inflation is more likely than good inflation, with inflation worse with a period of accelerated expansion is meant, which leads to a result which is contrary to the present observations. And a universe without inflation is more likely than one with inflation (according to Roger Penrose by a factor of 10100 ).
Eternal inflation: If inflation has begun, it never ceases due to quantum fluctuations on again. The result is a sea of inflationary expanding space, are embedded in the islets of hot matter and radiation - each of these islands a separate universe. According to Alexander Vilenkin universes form a bubble in which prevail physical states with a real vacuum, as we know it. These bubbles - our observable universe is such a bubble - remain surrounded by false vacuum, the ever expanding and always creates new bubbles.

Horizon problem

As the horizon problem, the fact is known that different, distant regions of the universe that do not contact each other, are homogeneous ( they have, despite the great distance the same physical properties ), although the big bang theory predict greater, measurable anisotropies of the night sky appears as those that have been previously observed.

The cosmological inflation is generally accepted as a solution for this. Is this correct?

Are there other possible explanations, such as a variable speed of light ( engl. variable speed of light (VSL ): c as a function of time and space, see variable speed of light) as a solution may be better suited?

Future of the universe

Which of the possible scenarios describing the future of the universe most likely:

Big Freeze, that is, an infinite expansion of the universe with concomitant cooling.

Big Rip, that is, an increasingly growing and finally extremely increasing emergence of new space, so that all objects are moving away from each other faster and no longer able to interact.

Big Crunch, that is, the expansion of the universe ends sometime in the future and then turns into a contraction is accelerating.

Big Bounce The Big Bounce theory is based on a quantization of space-time and avoids singularities such as the Big Bang theory ( according to which the universe at time zero an infinite density should have been ), since all physical quantities can only take finite values in their. The Big Bounce theory is derived from the model of the oscillating universe. It is assumed that the Big Bang was the result of the collapse ( Big Crunch ) of a previous universe.

Is the universe part of a infinitely repeating cycle (each of which, for example, starts with a big bang and a big crunch ends )?

Gravitational waves

As gravitational waves are called waves in space-time, which traverse the space with the speed of light and compress it and stretch it. They were in 1916 by Albert Einstein predicted as part of his general theory of relativity. Each system accelerated masses (eg, a binary star system or a circular motion around the sun Planet) then generates gravitational waves. To generate the orbit of the earth around the sun gravitational waves, but immeasurably weak. The radiated power amounts to just 300 watts.

Can gravitational waves be detected experimentally? To date, could be provided in any case, no experimental proof. The difficulty of the proof lies in the fact that even supernovae or supermassive black holes on earth cause only relative changes in length of 10-18 at best, typically only 10-21 even, ie a distance of 3 km length changes by only one-thousandth the diameter of a proton. Currently, run the following experiments for the detection of gravitational waves: GEO600 and LIGO. Expected 2015 LISA Pathfinder will be launched, which serves as a testing technology for the planned experiment LISA. In the distant future LISA then to be realized.

In a hitherto successful quantum field theoretical description of gravity, the gravitational interaction is mediated by hypothetical gravitons; that is, gravitational waves are radiated in gravitons called quantized units or absorbed.

If gravitons exist, they can then be detected experimentally?

Baryon asymmetry

The baryon asymmetry is the observed strong dominance of matter over antimatter in the universe.

Why is there so much more matter than antimatter in the observable universe? There are following approaches to answer:

1 Evidence for the existence of antimatter worlds:

It is envisioned that the universe consists of spatially separated areas, in each of which the baryonic or antibaryonische matter predominates: the incoming cosmic radiation on Earth is examined for antimatter, eg after anti- helium and even heavier anti- nuclei. By detecting, for example, of a single anti- carbon core would prove the existence of stars of antimatter in the universe, because carbon could not be formed in the Big Bang. However, all previous verification attempts went negative ( for example, by experiment or the two Pamela AMS experiments). Furthermore, argues against the existence of antimatter regions that in the border areas between matter and antimatter extremely energetic photons, resulting from the mutual annihilation of matter and antimatter would have to rise to what has been but has not been observed.

2 The preferred formation of baryons in the early universe:

The Sacharowkriterien are necessary conditions for a dynamic generation of the baryon asymmetry in the universe. The CP violation ( second Sakharov criterion) has been detected in four particles, but it alone can the observed matter-antimatter asymmetry in the Universe does not explain, because it is too small by a factor of 1010. (see also physics beyond the standard model: Item 3 )

Theories to explain the baryon asymmetry are eg

Baryogenesis
Leptogenesis
Higgsogenese: Are the Higgs boson and responsible ( hypothetical ) anti - particles for the baryon asymmetry?

Cosmological constant

The cosmological constant is a physical constant that was originally introduced by Albert Einstein in the general theory of relativity. The cosmological constant but is now no longer interpreted as a parameter of the general theory of relativity, but as the time-constant energy density of the vacuum.

Why the zero point energy of the vacuum does not cause such a large cosmological constant, as predicted by quantum field theories? What there is the opposite effect? (see also the unsolved problem: vacuum - disaster )

Dark Matter

The existence of dark matter - that is, not directly visible matter - is postulated in cosmology, because only the motion of the visible matter can be explained, in particular the rate at which encircle the center of their galaxy with the visible stars.

From what is dark matter?

Is it particles? If it is the lightest superpartner (or LSP)?

Or, the phenomena that are attributed to the dark matter, may not even be on a form of matter, but refers to the need for an extension of the theory of gravity? See, for example, Alternative explanations or MOND theory.

The results of the Large Underground Xenon experiment ( LUX ), which took place in 2013 in the Sanford Underground Research Facility, set a lower limit for the mass of the LSP; at the present time can therefore LSP, which were the main candidates for dark matter in the lower mass range, be excluded with 90 % certainty.

Dark Energy

The existence of dark energy is postulated as a hypothetical form of energy to explain the observed accelerated expansion of the universe.

What is the cause for the observed accelerated expansion of the universe ( de Sitter phase)?

Why is the energy density of the dark energy of the same order of magnitude as the present matter density, since the two are quite different but develop in time; it could not just be that we at exactly the right time to make the observation ( Anthropic Principle )?

What exactly is Dark Energy? Possible explanations for this are:

The cosmological constant
The vacuum energy
The quintessence

Copernican principle

The Copernican principle means that man takes no excellent, special position in the cosmos, but just a typical average.

Some large structures of the microwave sky, which are removed more than 13 billion light years, both seem to agree with the movement as well as the orientation of the solar system. Is it due to systematic errors in the collection and processing of data, there are local phenomena or is it, this is a violation of the Copernican principle? (see background radiation: Open questions )

The shape of the universe

Bzgl. the shape of the universe are the local and distinguish the global geometry:

Local geometry: the curvature of the ( observable ) Universe
Global Geometry: the topology of the universe as a whole ( observable and beyond: see also multiverse )

The local geometry of the universe is determined by the value of the density parameter Ω or through the space -time curvature parameter (see Friedmann equation) provides:

Ω > 1: spherical universe, since the energy density of the universe is greater than the critical energy density and thus the curvature of space- time is positive ( = 1)

Ω <1: hyperbolic universe, because the energy density is less than the critical value, and thus the curvature of the travel time is negative ( = -1)

Ω = 1: flat (ie, Euclidean ) universe, because the energy density is the same size as the critical energy density and thus the space-time vanishing curvature (= 0)

The local geometry does not determine the global geometry indeed complete, but it limits their possible values .

What is the 3-manifold of comoving space (English: comoving space), ie a co-moving space sector of the universe ( see also distance measure ), colloquially called the shape of the universe?

Neither the curvature nor the topology are presently known, although it is known that the curve - at least in the observed sizes - is close to zero. The hypothesis of cosmological inflation claims that the shape of the universe may not be noticeable, but since 2003, Jean -Pierre Luminet et al. proposed that the shape of the universe may be a dodecahedron topology.

If the shape of the universe a Poincare space, another 3-manifold or is the shape of the universe ever can not be determined?

Quantum gravity

The quantum gravity is currently in development theory, which is to unite quantum theory (QT ), and General Relativity (GR ). The quantum gravity is considered a possible candidate for a TOE ( Theory Of Everything).

Why is an association of QT and ART even necessary? The QT and the ART have any problems on themselves, moreover, they are very different, because the ART is purely classical. If the total physics be logically consistent, so there must be a theory that combines the QT and the ART in any form. A theory of quantum gravity, which is to replace the QT and the ART needs, their internal contradictions dissolve and contain both theories as limiting cases. You must make the same statements about nature, who supplied us the standard models of particle physics and modern cosmology. You must also answer a key problem of QT: Where is the dividing line between classical and quantum mechanical world.

Issues of ART:

The existence of black holes with a singularity at its center; Points of infinite curvature of space and infinite density, when describing all known laws of physics break down.

The big bang singularity with infinite density and temperature

Stephen Hawking's discovery that black holes can dematerialize - a quantum field theoretical knowledge, which contradicts the predictions of ART.

Problems of the QT:

Where is the dividing line between classical and quantum mechanical world?

The occurrence of infinite terms in the mathematical expressions using sophisticated rules ( renormalization ) must be eliminated

Furthermore, the question has to the nature of space and time at the shortest distances - the so-called Planck length ( 10-35 meters ) and the Planck time ( 10-43 seconds) - to be answered:

Space and time are continuous, as it assumes the ART?

Or space and time are quantized? So if there is the space of discrete pieces, ie irreducible volume elements, which can not be further split? And running out of time into tiny, discrete steps? The space-time would thus be a granular structure from the hypothetical space-time - atoms have (analogous to the atoms of the material ).

A central problem of a theory of quantum gravity would be that the space-time geometry is no longer ( as in quantum theory ) can be taken as given, but that the space-time geometry itself is subject to quantum fluctuations.

Theory of quantum gravity

Candidate for a theory of quantum gravity are:

String theory
M-theory
Loop quantum gravity
Twistor theory

Can quantum mechanics and general relativity are combined into a consistent theory ( possibly as a quantum field theory )?

If the space-time continuous or discrete, ie quantized (see also Planck units: Planck length )?

Would a consistent theory include a force whose carrier is the hypothetical graviton (see string theory ) or they would be the result of the quantized structure of space- time itself (as in loop quantum gravity )?

Are there any deviations from the predictions of general relativity in both the microscopic and the macroscopic field or in other extreme conditions that result from a theory of quantum gravity?

(see also the unsolved problem: Guess to protect the time of order or time sequence )

Vacuum disaster

As a vacuum catastrophe, the fact is referred to that of the theoretically predicted value of the vacuum energy of the universe by a factor of 10120 is larger than the actually observed value. (see also the unsolved problem: cosmological constant )

What is the reason for this huge discrepancy?

Why does the predicted mass of the quantum vacuum have little effect on the expansion of the universe?

Black holes and singularities

Black Hole: black holes produce thermal radiation ( Hawking radiation), as suspected from theoretical predictions?

Hawking radiation: Does this radiation information about the internal structure of the black holes, like from the gauge theory / gravity duality (English gauge / gravity duality ) suspected? Or it contains no information about how it is thought of Stephen Hawking's original calculation?

Information paradox: If the radiation but contains no information and can evaporate black holes, what happens to the information that is contained in the black holes ( quantum mechanics sees a loss of information not available)? Or listen to the radiation at a given time and leaves the remains of a black hole? Are there other ways to examine the internal structure of black holes, provided that such a structure exists at all? (See also No - hair theorem)

Cosmic censorship hypothesis (german cosmic censorship hypothesis ): It was originally set up and claimed that naked singularities in the Universe by Roger Penrose in 1969 - with the exception of the big bang singularity - can not exist. Is it possible to prove this hypothesis in some form? Or can naked singularities, that is, Singularities which are not hidden behind an event horizon, arising from realistic initial conditions?

Additional dimensions

Is there in nature more than four space-time dimensions? If so, what is their number and their size? The following theories postulate more than four space-time dimensions:

String theory: 10
Supergravity: 11,
Boson string theory: 26
M-theory: 11

Are dimensions a fundamental property of the universe or are they the result of different physical laws?

If we can prove higher space dimensions experimentally?

Location

Locality called in physics the property of a theory that processes only affect their immediate physical environment. In non-locality and locality it is in principle to the question of whether or under what conditions an event can influence another event.

According to the Bell 's inequality, a physical theory is local if, when two spatially separated particles, the choice of what is measured when a particle in the measurement does not directly affect the other particle. Quantum mechanics violates Bell's inequality.

Are there except the quantum entanglement or other non-local phenomena in quantum physics?

Can information and properties are transferred in a non-local way?

The conditions under which non-local phenomena are observed?

What does the existence or non-existence of non-local phenomena on the fundamental structure of space- time? What is the relationship in this case, the quantum entanglement?

Presumption to protect the order of time

If the CTC, excluded from a theory of quantum gravity, which combines general relativity and quantum mechanics, as Stephen Hawking proposed in the CPC? (see also the unsolved problem: theory of quantum gravity )

High Energy Physics / Particle Physics

Higgs mechanism

Through the Higgs mechanism is the mass of the fundamental particles, a previously interpreted as originally viewed property as a result of a new type of interaction. However, the cause of the mass of the Higgs boson itself eludes this interpretation, it remains unexplained.

Is there only the one found at CERN Higgs boson or is there still more Higgs bosons? (see also physics beyond the standard model: Item 1)

If the decay channels of the Higgs boson with the Standard Model agree?

If the Higgs boson and its ( hypothetical ) anti - particles responsible for the baryon asymmetry? (see also the unsolved problem baryon asymmetry )

Hierarchy problem

In particle physics, the hierarchy problem refers to the question of why gravity so much weaker ( by a factor of 10-32 ) than the electroweak interaction.

The gravity is strong for elementary only at the Planck scale, at about 1019 GeV, a lot of times the magnitude of the weak interaction. However, the Planck scale is 16 orders of magnitude above the electroweak scale ( 103 GeV scale ). The effective (ie experimentally accessible ) Higgs mass whose value you need for the Higgs mechanism in the electroweak scale, so is not in their natural value near the Planck mass ( naturalness problem).

Why the magnitudes are so far apart? (see also physics beyond the standard model: point 2)

Magnetic monopole

A magnetic monopole is an imaginary magnet, which has only one pole. By Paul AM Dirac comes the speculation that there could be the magnetic monopole as the elementary particles, which would be the magnetic counterpart of the electron.

If there are elementary particles that carry or have they existed in the past a magnetic charge (analogous to electric charge )?

Speak two arguments for this idea:

The asymmetry between the otherwise similar phenomena magnetism and electricity - visible, for example in the Maxwell equations - would be resolved, electrical and magnetic phenomena were strictly " dual" to each other.

According to Dirac, the presence of magnetic monopoles would explain the quantization of electric charge.

Proton

Proton decay: Is the proton fundamentally stable? Or does it have predicted only a very large half-life (greater than 1031 years ) and therefore disintegrates within a finite period of time, such as some variants of the grand unified theory (GUT)?

Spin crisis (English proton spin crisis ): Who is the carrier of proton spin: quarks, gluons or both?

The total spin of the proton is made up of the spins of the valence quarks, sea quarks and the gluons and the angular momenta of quarks and gluons. To date, it has not yet succeeded in accurately divide the total spin of the proton from these components. Also theoretical models and experiments seem to give different contributions of the quarks to the total spin of the proton. According to the following source, the spin of the proton is composed as follows: the quark spin contributes approximately at, while the shares of gluon spin, quark- gluon angular momentum and angular momentum are both unknown.

Supersymmetry

Supersymmetry is a hypothetical symmetry of particle physics, bosons ( particles with integer spin) and fermions ( particles with half-integer spin) into each other. Most Grand Unified Theories and superstring theories are supersymmetric. However, it was rendered to date, no experimental evidence that supersymmetry actually exists in nature.

If the space-time supersymmetry in the range of TeV? If so, what mechanism causes the supersymmetry is broken?

Stabilizes the supersymmetry in the field of electro-weak interaction?

Is this part of the LSP dark matter? (see also the unsolved problem of dark matter )

Generation

In particle physics, the elementary particles of matter known twelve are divided into three so-called generations of four particles plus their antiparticles. The existence of a fourth, fifth, etc. with corresponding generation not yet experimentally proven elementary particles can not be excluded, but there are no indications for future generations known.

Why are there just three generations ( each with two flavors ) of fundamental fermions ( quarks and leptons )? (see also physics beyond the standard model: Item 4 )

Is there a theory that can explain the mass of certain quarks and leptons in certain generations based on overriding principles ( eg, based on a theory of Yukawa coupling)?

Spontaneous symmetry breaking

Spontaneous symmetry breaking is a concept of theoretical physics, the Standard Model of elementary particle physics in particular plays an important role.

What is the cause for the symmetry breaking of the electroweak gauge symmetry, which gives the W and Z bosons mass:

Higgs mechanism of the Standard Model
Technicolor (breaking of the electroweak symmetry as a result of the interaction dynamics)

Neutrino

In today's standard model of particle physics neutrinos have no mass.

Neutrino oscillation experiments have shown that neutrinos have a nonzero rest mass. There are also theories that predict a non-zero mass. What is the neutrino mass?

Are neutrinos Dirac fermions or Majorana fermions ( particles that their own antiparticles are the same)?

If the mass hierarchy normal or inverted?

Violates the neutrino CP symmetry ( phase factor δ is different from zero )?

Confinement

Confinement referred in particle physics, the phenomenon that particles with color charge - quarks and gluons - not isolated, ie do not occur as free particles, but only in elementary particles, which are composed of them, such as Mesons and baryons.

As can be seen this phenomenon of quantum chromodynamics?

Strong CP problem

Under CP violation (C for engl batch charge;. P for parity Parity ) is the violation of the CP invariance. The latter states that the physical relationships and regularities in a system should not change when all particles are replaced by their antiparticles, while all spatial coordinates are mirrored.

Strong CP problem ( engl. strong CP problem): Why could not for the strong interaction is no CP violation - which should be possible in principle - be demonstrated experimentally?

Axion: If the Peccei -Quinn theory and hypothetical elementary particles Axion the solution to the strong CP problem? Can axions be demonstrated experimentally?

Anomalous magnetic moment

Why is the experimentally measured value of the anomalous magnetic moment of the muon (g- 2) from the theoretically predicted by the standard model value is different?

Astronomy and Astrophysics

Accretion disk

An accretion disk is in astrophysics a rotating disk around a central object, the material transported in the direction of the center ( accreted ). It may consist of atomic gas or dust or from different degrees of ionized gas ( plasma).

Jets: Why develop jets perpendicular to the plane of rotation of certain astronomical objects, such as galactic nuclei or black holes that accumulate matter by means of a rotating accretion disk?

Quasi- periodic oscillations (English quasi- periodic oscillations ): Why do many accretion disks on quasi- periodic oscillations? Why is the period of oscillation is inversely proportional to the mass of the central object? Why is there sometimes harmonics and why these occur at different objects in various frequency ratios?

Solar corona

The solar corona is the area of the sun's atmosphere that lies above the chromosphere and is characterized by significantly lower densities and higher temperatures compared to the deeper layers of the solar atmosphere.

Heating of the corona: Why is the temperature of the corona (typically several million Kelvin) significantly hotter than the temperature of the underlying layers of the solar chromosphere and photosphere as ( surface of the sun )?

Possible explanations for the heating of the corona include the dissipation of plasma waves, reconnection continuously restructured magnetic field configurations, shock- dominated dissipation of electric currents, heating by shock waves and other possible processes.

Reconnection: Why is the magnetic reconnection many orders of magnitude faster than predicted by standard models?

Supermassive black holes

The M- sigma relation ( M - relation) is an empirically determined relationship between the mass M of a supermassive black hole ( include up to several billion solar masses ) in the center of a galaxy and the velocity dispersion of stars in the dense central region of a spiral galaxy ( bulge ).

What is the reason for the M- sigma relation?

How did the most distant quasars amassed their supermassive black holes so early in the history of the universe?

UHECR

Where did the ultra-high energy cosmic rays (german ultra - high-energy cosmic ray and UHECR )?

Why are there cosmic rays with unlikely high energy (see OMG particle)? The particles of the cosmic radiation maximum of 50 Mpc to go far in such a circle around the earth but are none of the possible sources.

Why has cosmic radiation from distant sources manifestly derived energies above the GZK cutoff?

Others

Diffuse interstellar bands: What is responsible for the numerous absorption lines in diffuse interstellar bands? If it is molecules that are there?

Gamma-ray burst: the bursts in ten seconds more energy than the sun in billions of years. What is the cause for the emergence of gamma-ray bursts?

Kuiper cliff (English Kuiper cliff ): Why is the number of objects falling in the Kuiper Belt of our solar system beyond a limit of 50 AE unexpectedly and quickly?

Fly-by anomaly: Several spacecraft have experienced at a fly-by to Earth a little extra and unexpected increase in speed. What is the cause of this?

Problem of the rotation curve of galaxies: What causes the difference in the observed and theoretically predicted velocity of stars that move around the center of galaxies? Is dark matter the cause? Or must the theories be adapted, for example, Modified Newtonian dynamics?

Supernova: What is the precise mechanism by which to describe the transition from the collapse of the core ( implosion ) to the actual explosion of the star?

Magnetar: What causes the extremely strong magnetic field of a magnetar?

Rotation rate of Saturn: Why the magnetosphere of Saturn shows a slowly varying periodicity, which is similar to the rate of rotation of the clouds on Saturn? What is the rate of rotation of the inner member (or the fixed core ) of the Saturn?

Roar of space (English space roar ): Why is the roar of space six times louder than expected? What is the source for this?

Age - metallicity relation: Is there a universally valid relation between age and metallicity in galaxies?

Nuclear physics

Nuclear physics is the branch of physics that deals with the structure and behavior of atomic nuclei. Its key theoretical tool is the quantum mechanics.

Quantum chromodynamics

Quantum chromodynamics ( QCD ) is a quantum field theory describing the strong interaction. It describes the interaction of quarks and gluons, which is the fundamental building blocks of atomic nuclei. The QCD is like quantum electrodynamics ( QED ) is a gauge theory. However, the description of the nucleons is an open problem. The quarks have only 5 % of the mass of the nucleons, the remaining 95 % of the nucleon are taken from the binding energy of the strong interaction and the kinetic energy of the quarks and gluons making up the nucleons.

What are the phases of strongly interacting matter, and what is their role in the cosmos? What is the internal structure of the nucleon? What does the QCD ahead regarding the properties of strongly interacting matter?

What determines the transition of quarks and gluons into pions and nucleons?

What role gluons and interactions between gluons in nucleons and nuclei? If there are glueballs ( hypothetical, color charge-neutral particles consisting only of gluons )? Win gluons dynamically within hadrons mass, although they have a rest mass of zero?

What determines the essential features of QCD and how they relate to gravity and space-time?

Why could still be detected for the QCD no CP violation? Assigns the QCD really no CP violation on? (see also the unsolved problem: strong CP problem)

Atomic nuclei and nuclear astrophysics

The strong interaction is used to explain the bond between the quarks in the hadrons. Before the introduction of the quark model was referred to as the strong interaction force of attraction between the nucleons (protons and neutrons) the atomic nucleus. This attractive force between nucleons is nowadays referred to as residual interaction or nuclear power. A complete description of these nuclear power from the quantum chromodynamics is not yet possible.

What is the nature of the residual interaction that holds together the protons and neutrons in stable nuclei (see also magic nuclei ) and isotopes?

What is the origin of simple patterns in complex nuclei? What is the nature of exotic excitations in nuclei at the limit of stability and its role in the physical processes of stars?

What is the nature of neutron stars and densely packed matter? What are the physical processes of stars and stellar explosions?

Atomic physics

The atomic physics is the branch of physics that deals with the physics of the atomic shell and the processes taking place in their operations. The atomic physics considered the nucleus as not further divisible module.

Hydrogen / helium

What is the solution of the Schrödinger equation for the hydrogen atom in arbitrary electric and magnetic fields?

The helium atom is the simplest three-body problem in quantum mechanics. There are approximate solutions of the Schrödinger equation for the helium atom. Is there an exact solution?

Myonischer hydrogen

Is the radius of muonic hydrogen ( the electron is replaced here by a muon ) with the radius of ordinary hydrogen agree: yes or no? see also muonium or exotic atom.

Condensed Matter Physics

The physics of condensed matter differs due to the mutual interaction of the building blocks of matter significantly from the free particles ( elementary particle physics, nuclear physics ). The theoretical description is based on the many-body theory.

High temperature superconductors

As a high-temperature superconductor materials are referred to, whose superconductivity - unlike conventional superconductors - does not come through the electron -phonon interaction about. The cause is unknown for more than 25 years.

Which mechanism is the cause that some materials exhibit superconductivity at temperatures of considerably more than 25 Kelvin?

Is it possible to produce a material which at room temperature (20 ° C or 292 Kelvin) is superconducting?

Amorphous materials

The amorphous material is called a substance in which the atoms no ordered structures, but an irregular pattern form and only on short-range order, but do not have long-range order. In contrast to amorphous hot regularly structured materials crystals.

What is the nature of the glass transition (see glass transition temperature ) between a liquid or solid and the glass phase?

What physical processes are responsible for the properties of glasses and the glass transition?

Sonoluminescence

Under sonoluminescence is defined as a physical phenomenon in which a liquid ultrashort under strong pressure fluctuations, high-energy flashes of light emits.

What is the cause of these short, high-energy flashes of light emanating from imploding cavitation bubbles in a liquid when it bubbles were previously produced artificially with appropriate ultrasound intensity and frequency?

Turbulence

Turbulence is the movement of liquids and gases, occur in the turbulence on all scales. This type of flow is characterized by mostly three-dimensional, seemingly random movements of the fluid particles (see also turbulence model ).

Can a theoretical model be created (in particular its internal structure ) to describe the statistics of a turbulent flow?
Under what conditions exist exact solutions of the Navier -Stokes equations? This problem is also one of the Millennium Problems of Mathematics.

Others

Topological order: Is the topological order at temperatures above 0 K stable?

Quantum Hall Effect: What mechanism explains the existence of the non - integer ν = 5/2 state in the fractional QHE? Are anyons responsible?

Bose -Einstein condensate: Can the existence of Bose - Einstein condensates are proved for interacting systems?

Liquid Crystals: Can the transition from the nematic to the smectic phase in liquid crystals as a universal phase transition are considered?

Quantum dot: What is the cause of the Nichtparabolizität (English nonparabolicity ) in the conduction band of quantum dots?

Band structure: Can the band structure and band gaps are also calculated exactly? Only approximate solutions have been used for the calculation of the band structure of a material, such as Model of the quasi-free electron, tight-binding method or density functional theory ( DFT).

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