Super-heavy fermion material as metallic refrigerant for adiabatic demagnetization cooling

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, as the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with $^3$He gas are widely used for cooling below 1 Kelvin. However, usage of the gas is being increasingly difficult due to the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. Here, we show that a new type of refrigerant, super-heavy electron metal, YbCo$_2$Zn$_{20}$, can be used for adiabatic demagnetization refrigeration, which does not require 3He gas. A number of advantages includes much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb$_{1-x}$Sc$_x$Co$_2$Zn$_{20}$ by partial Sc substitution with $x\sim$0.19. The substitution induces chemical pressure which drives the materials close to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures enabling final temperatures well below 100 mK. Such performance has up to now been restricted to insulators. Since nearly a century the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for the cryogen-free refrigeration

Надписи от Кабиле. Нови прочити и тълкувания: Inscriptions from Cabyle: New readings and interpretations

The article proposes revised reading of several inscriptions from Cabyle. Two Hellenistic fragments are shown to belong to a decree honouring Kriton, son of Euma[chos] or Euma[res], who was put in charge of the city or the neighbouring territories and provided many great services to the citizens. Two alleged mentions of Celts (Γαλά[ται]) in Hellenistic fragments are proved to be misreading. In two inscriptions of AD 135-136, the nomen of the provincial governor ---rius Fronto is reconstructed as Cavarius. A consular date corresponding to AD 208 is restored in an inscription for the construction of a temple for Jupiter Optimus Maximus Dolichenus, which provides a date for the governor of Thrace Q. Egnatius Proculus. Several inscriptions are shown to mention military officers – a prefect, a centurion, and a duplicarius. A fragment erroneously thought to belong to a funerary monument is now read as a dedication to Phoebus and is identified as a fragment from a statue of the god. A Greek inscription, which was only partially read and incorrectly dated to the first half of the third century, in fact belongs to the period of the First Tetrarchy and documents the building of the fortifications of Cabyle under the governor Domitius Domninus in AD 297. Another inscription, from the time of the Fourth Tetrarchy (AD 309-310), is about the construction of a gynaeceum (state textile workshop), being the only such inscription hitherto found on the territory of the Roman Empire. The two tetrarchic inscriptions also reveal the new status of Cabyle in that period – previously a military camp (castra), it was raised to a city, with the title “the splendid city of Cabyle” (ἡ λαμπρὰ Καβυληνῶν πόλις). The main magistrate of the new city was the λογιστής (= curator civitatis), and the first members of the city’s curia were called δεκάπρωτοι (as a translation of the Latin decemprimi)

“God’s Grace is a Gain”: Dipinti on a Sixth- Century Amphora from Trimammium

The paper publishes an amphora with dipinti from the sixth century AD, found in the military camp of Trimammium on the Lower Danube limes (the Late Antique province of Moesia Secunda). A six-line dipinto on the one side includes invocations and information about the content of the amphora. The dipinti on the other side are abbreviations, possibly for a personal name and for the name of Trimammium, where the amphora had been exported to. The amphora originated from the Eastern provinces and contained oil, which was possibly used during church services

Ancient Theatre and Performance Culture around the Black Sea

This is the first study of ancient theatre and performance around the coasts of the Black Sea. It brings together key specialists around the region with well-established international scholars on theatre and the Black Sea, from a wide range of disciplines, especially archaeology, drama and history. In that way the wealth of material found around these great coasts is brought together with the best methodology in all fields of study. This landmark book broadens the whole concept and range of theatre outside Athens. It shows ways in which the colonial world of the Black Sea may be compared importantly with Southern Italy and Sicily in terms of theatre and performance. At the same time, it shows too how the Black Sea world itself can be better understood through a focus on the development of theatre and performance there, both among Greeks and among their local neighbours