In theoretical physics, the dual graviton is a hypothetical elementary particle that is a dual of the graviton under electric-magnetic duality, as an S-duality, predicted by some formulations of supergravity in eleven dimensions.[3]
The dual graviton was first hypothesized in 1980.[4] It was theoretically modeled in 2000s,[1][2] which was then predicted in eleven-dimensional mathematics of SO(8) supergravity in the framework of electric-magnetic duality.[3] It again emerged in the E11 generalized geometry in eleven dimensions,[5] and the E7 generalized vielbein-geometry in eleven dimensions.[6] While there is no local coupling between graviton and dual graviton, the field introduced by dual graviton may be coupled to a BF model as non-local gravitational fields in extra dimensions.[7]
A massive dual gravity of Ogievetsky-Polubarinov model[8] can be obtained by coupling the dual graviton field to the curl of its own energy-momentum tensor.[9][10]
The previously mentioned theories of dual graviton are in flat space. In de Sitter and anti-de Sitter spaces (A)dS, the massless dual graviton exhibits less gauge symmetries dynamics compared with those of Curtright field in flat space, hence the mixed-symmetry field propagates in more degrees of freedom.[11] However, the dual graviton in (A)dS transforms under GL(D) representation, which is identical to that of massive dual graviton in flat space.[12] This apparent paradox can be resolved using the unfolding technique in Brink, Metsaev, and Vasiliev conjecture.[13][14] For the massive dual graviton in (A)dS, the flat limit is clarified after expressing dual field in terms of the Stueckelberg coupling of a massless spin-2 field with a Proca field.[11]
https://en.wikipedia.org/wiki/Dual_graviton
The Xi baryons /ksaɪ bæriənz/ or cascade particles are a family of subatomic hadron particles which have the symbol Ξ and may have an electric charge (Q) of +2 e, +1 e, 0, or −1 e, where e is the elementary charge.
Like all conventional baryons, Ξ particles contain three quarks. Ξ baryons, in particular, contain either one up or one down quark and two other, more massive quarks. The two more massive quarks are any two of strange, charm, or bottom (doubles allowed). For notation, the assumption is that the two heavy quarks in the Ξ are both strange; subscripts "c" and "b" are added for each even heavier charm or bottom quark that replaces one of the two presumed strange quarks.
They are historically called the cascade particles because of their unstable state; they are typically observed to decay rapidly into lighter particles, through a chain of decays (cascading decays).[1] The first discovery of a charged Xi baryon was in cosmic ray experiments by the Manchester group in 1952.[2] The first discovery of the neutral Xi particle was at Lawrence Berkeley Laboratory in 1959.[3] It was also observed as a daughter product from the decay of the omega baryon (
Ω−
) observed at Brookhaven National Laboratory in 1964.[1] The Xi spectrum is important to nonperturbative quantum chromodynamics (QCD), such as lattice QCD.[why?]
https://en.wikipedia.org/wiki/Xi_baryon
The lambda baryons (Λ) are a family of subatomic hadron particles containing one up quark, one down quark, and a third quark from a higher flavour generation, in a combination where the quantum wave function changes sign upon the flavour of any two quarks being swapped (thus differing from a sigma baryon). They are thus baryons, with total isospin of 0, and have either neutral electric charge or the elementary charge +1.
https://en.wikipedia.org/wiki/Lambda_baryon
The Delta baryons (or Δ baryons, also called Delta resonances) are a family of subatomic particle made of three up or down quarks (u or d quarks).
Four closely related Δ baryons exist:
Δ++
(constituent quarks: uuu),
Δ+
(uud),
Δ0
(udd), and
Δ−
(ddd), which respectively carry an electric charge of +2 e, +1 e, 0 e, and −1 e. The Δ baryons have a mass of about 1232 MeV/c2, a spin of 3⁄2, and an isospin of 3⁄2. Ordinary protons and neutrons (nucleons (symbol N)), by contrast, have a mass of about 939 MeV/c2, a spin of 1⁄2, and an isospin of 1⁄2. The
Δ+
(uud) and
Δ0
(udd) particles are higher-mass excitations of the proton (
N+
, uud) and neutron (
N0
, udd), respectively. However, the
Δ++
and
Δ−
have no direct nucleon analogues.
The states were established experimentally at the University of Chicago cyclotron[1][2] and the Carnegie Institute of Technology synchro-cyclotron[3] in the mid-1950s using accelerated positive pions on hydrogen targets. The existence of the
Δ++
, with its unusual +2 charge, was a crucial clue in the development of the quark model.
The Delta states discussed here are only the lowest-mass quantum excitations of the proton and neutron. At higher masses, additional Delta states appear, all defined by having 3⁄2 units of isospin, but with a spin quantum numbers including 1⁄2, 3⁄2, 5⁄2, ... 11⁄2. A complete listing of all properties of all these states can be found in Beringer et al. (2013).[4]
There also exist antiparticle Delta states with opposite charges, made up of the corresponding antiquarks.
https://en.wikipedia.org/wiki/Delta_baryon
A magnon is a quasiparticle, a collective excitation of the electrons' spin structure in a crystal lattice. In the equivalent wave picture of quantum mechanics, a magnon can be viewed as a quantized spin wave. Magnons carry a fixed amount of energy and lattice momentum, and are spin-1, indicating they obey boson behavior.
https://en.wikipedia.org/wiki/Magnon
In theoretical physics, a roton is an elementary excitation, or quasiparticle, seen in superfluid helium-4 and Bose–Einstein condensates with long-range dipolar interactions or spin-orbit coupling. The dispersion relation of elementary excitations in this superfluid shows a linear increase from the origin, but exhibits first a maximum and then a minimum in energy as the momentum increases. Excitations with momenta in the linear region are called phonons; those with momenta close to the minimum are called rotons. Excitations with momenta near the maximum are called maxons.
The term "roton" is also used for the quantized eigenmode of a freely rotating molecule.[citation needed]
https://en.wikipedia.org/wiki/Roton
In physics, chemistry, and electronic engineering, an electron hole (often simply called a hole) is the lack of an electron at a position where one could exist in an atom or atomic lattice. Since in a normal atom or crystal lattice the negative charge of the electrons is balanced by the positive charge of the atomic nuclei, the absence of an electron leaves a net positive charge at the hole's location.
Holes in a metal[1] or semiconductor crystal lattice can move through the lattice as electrons can, and act similarly to positively-charged particles. They play an important role in the operation of semiconductor devices such as transistors, diodesand integrated circuits. If an electron is excited into a higher state it leaves a hole in its old state. This meaning is used in Auger electron spectroscopy (and other x-ray techniques), in computational chemistry, and to explain the low electron-electron scattering-rate in crystals (metals, semiconductors). Although they act like elementary particles, holes are not actually particles, but rather quasiparticles; they are different from the positron, which is the antiparticle of the electron. (See also Dirac sea.)
In crystals, electronic band structure calculations lead to an effective mass for the electrons, which is typically negative at the top of a band. The negative mass is an unintuitive concept,[2] and in these situations, a more familiar picture is found by considering a positive charge with a positive mass.
https://en.wikipedia.org/wiki/Electron_hole
The
J/ψ
(J/psi) meson /ˈdʒeɪ ˈsaɪ ˈmiːzɒn/ or psion[1] is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium". The
J/ψ
is the most common form of charmonium, due to its spin of 1 and its low rest mass. The
J/ψ
has a rest mass of 3.0969 GeV/c2, just above that of the
η
c (2.9836 GeV/c2), and a mean lifetime of 7.2×10−21 s. This lifetime was about a thousand times longer than expected.[2]
Its discovery was made independently by two research groups, one at the Stanford Linear Accelerator Center, headed by Burton Richter, and one at the Brookhaven National Laboratory, headed by Samuel Ting of MIT. They discovered they had actually found the same particle, and both announced their discoveries on 11 November 1974. The importance of this discovery is highlighted by the fact that the subsequent, rapid changes in high-energy physics at the time have become collectively known as the "November Revolution". Richter and Ting were awarded the 1976 Nobel Prize in Physics.
https://en.wikipedia.org/wiki/J/psi_meson
In supergravity theories combining general relativity and supersymmetry, the gravitino (
G͂
) is the gauge fermion supersymmetric partner of the hypothesized graviton. It has been suggested as a candidate for dark matter.
If it exists, it is a fermion of spin 32 and therefore obeys the Rarita-Schwinger equation. The gravitino field is conventionally written as ψμα with μ = 0, 1, 2, 3 a four-vector index and α = 1, 2 a spinor index. For μ = 0 one would get negative norm modes, as with every massless particle of spin 1 or higher. These modes are unphysical, and for consistency there must be a gauge symmetry which cancels these modes: δψμα = ∂μεα, where εα(x) is a spinor function of spacetime. This gauge symmetry is a local supersymmetry transformation, and the resulting theory is supergravity.
Thus the gravitino is the fermion mediating supergravity interactions, just as the photon is mediating electromagnetism, and the graviton is presumably mediating gravitation. Whenever supersymmetry is broken in supergravity theories, it acquires a mass which is determined by the scale at which supersymmetry is broken. This varies greatly between different models of supersymmetry breaking, but if supersymmetry is to solve the hierarchy problem of the Standard Model, the gravitino cannot be more massive than about 1 TeV/c2.
https://en.wikipedia.org/wiki/Gravitino
N = 4 supersymmetric Yang–Mills (SYM) theory is a mathematical and physical model created to study particles through a simple system, similar to string theory, with conformal symmetry. It is a simplified toy theory based on Yang–Mills theory that does not describe the real world, but is useful because it can act as a proving ground for approaches for attacking problems in more complex theories.[1] It describes a universe containing boson fields and fermion fields which are related by 4 supersymmetries (this means that swapping boson, fermion and scalar fields in a certain way leaves the predictions of the theory invariant). It is one of the simplest (because it has no free parameters except for the gauge group) and one of the few finite quantum field theories in 4 dimensions. It can be thought of as the most symmetric field theory that does not involve gravity.
https://en.wikipedia.org/wiki/N_%3D_4_supersymmetric_Yang–Mills_theory
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