August 21st, 2020

лошадь, диаграмма, Фейнман

Надо бы почитать...

Emergent particles and gauge fields in quantum matter: https://arxiv.org/abs/2008.08799
Ben J. Powell
I give a pedagogical introduction to some of the many particles and gauge fields that can emerge in correlated matter. The standard model of materials is built on Landau's foundational principles: adiabatic continuity and spontaneous symmetry breaking. These ideas lead to quasiparticles that inherit their quantum numbers from fundamental particles, Nambu-Goldstone bosons, the Anderson-Higgs mechanism, and topological defects in order parameters. I then describe the modern discovery of physics beyond the standard model. Here, quantum correlations (entanglement) and topology play key roles in defining the properties of matter. This can lead to fractionalised quasiparticles that carry only a fraction of the quantum numbers that define fundamental particles. These particles can have exotic properties: for example Majorana fermions are their own antiparticles, anyons have exchange statistics that are neither bosonic nor fermionic, and magnetic monopoles do not occur in the vacuum. Gauge fields emerge naturally in the description of highly correlated matter and can lead to gauge bosons. Relationships to the standard model of particle physics are discussed.
Comments: Pedagogical review submitted to Contemporary Physics; 50 pages, 20 figures
лошадь, диаграмма, Фейнман

Терапия опухолей ионами гелия

Helium beam particle therapy facility
Mariusz Sapinski
Due to its precision and limited side effects, the particle therapy of cancer is gaining popularity. The number of patients treated with protons and light ions reached 150,000 worldwide. There are currently more than 80 facilities, which often this treatment and several dozen of new ones are in construction. Mostly they are cyclotron-based facilities, which provide proton beams, and only several are synchrotron-based facilities that provide both: proton and carbon-ion beams. The advantage of carbon ions is their higher efficiency in destroying the cancer cells, more localized shape of the Bragg peak and smaller beam scattering in the body. Several of the large centers, which can provide carbon, have experimented with other ions including helium. The advantage of helium over protons is significantly larger precision of the treatment due to lower scattering of alpha particles in the body, especially important for pediatric patients. A facility with therapeutic beams limited to helium, would be smaller and cheaper than carbon-based facility. Here we discuss this option.
лошадь, диаграмма, Фейнман

Котопятница сегодня удалась!

Сегодня наблюдал, как дикая кошь охотится и кушает:)) Желающие предлставить себе место действия, могут глянуть сюда. Итак, иду я по той дорожке в поисках птичек, и из-за поворота мне открывается Кошь, внимательно прислушивающаяся к чему-то в траве:


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