Demonstration of efficient nonreciprocity in a microwave optomechanical circuit

The ability to engineer nonreciprocal interactions is an essential tool in modern communication technology as well as a powerful resource for building quantum networks. Aside from large reverse isolation, a nonreciprocal device suitable for applications must also have high efficiency (low insertion loss) and low output noise. Recent theoretical and experimental studies have shown that nonreciprocal behavior can be achieved in optomechanical systems, but performance in these last two attributes has been limited. Here we demonstrate an efficient, frequency-converting microwave isolator based on the optomechanical interactions between electromagnetic fields and a mechanically compliant vacuum gap capacitor. We achieve simultaneous reverse isolation of more than 20 dB and insertion loss less than 1.5 dB over a bandwidth of 5 kHz. We characterize the nonreciprocal noise performance of the device, observing that the residual thermal noise from the mechanical environments is routed solely to the input of the isolator. Our measurements show quantitative agreement with a general coupled-mode theory. Unlike conventional isolators and circulators, these compact nonreciprocal devices do not require a static magnetic field, and they allow for dynamic control of the direction of isolation. With these advantages, similar devices could enable programmable, high-efficiency connections between disparate nodes of quantum networks, even efficiently bridging the microwave and optical domains.Comment: 9 pages, 6 figure

The study of metal nitride layer formation by solid-state reactions

A new solid-state reaction to form metal nitrides has been investigated. It was confirmed that single phase chromium nitride is formed by a solid-state diffusion reaction between iron nitride and chromium chloride powders at temperatures between 570-700°C. The discovered reaction can be applied to form chromium nitride coatings on tool steels for metal forming applications

FAMILY IN PALLIATIVE CARE

Sve se više otvoreno govori i znanstveno razmatra proces umiranja i smrti neizlječivo bolesnih osoba. Sve glasnije se ističu ljudska prava i potrebe umirućih te njihovih bližnjih. Iako je obitelj prepoznata kao punopravni korisnik palijativne skrbi, još se uvijek nedovoljno pozornosti posvećuje specifičnom procesu promjene što zahvaća obitelj u stresnom razdoblju gubitka člana. Zato je neophodno, osim umirućeg, u fokusu imati i obitelj te pozornost pridati sljedećim temama: obilježjima suvremene obitelji, suočavanju s umiranjem i smrti, palijativnoj skrbi o obitelji, palijativnoj skrbi u obitelji, komunikaciji te osjećajima i tugovanju u obitelji. Namjera je ovog rada sistematizacija postojećih pojedinačnih teorijskih spoznaja i njihovo integriranje u tematske cjeline. Prikaz temeljnih zaključaka treba omogućiti bolje razumijevanje značaja i uloge obitelji u skrbi za umiruće te učinkovitije planiranje i pružanje neophodne stručne pomoći i podrške.The process of dying and death of terminally ill persons is increasingly openly mentioned and scientifically analysed. Human rights and needs of the dying and their near ones are pointed out more loudly. Although the family is recognised as a valid user of palliative care, insufficient attention is still paid to the specific process of the change that the family undergoes in the stressful period of losing a member. Therefore it is necessary to have the focus not only on the dying person, but their family as well, and to pay attention to the following topics: characteristics of a modern family, facing dying and death, palliative care abut the family, palliative care in the family, communication and feelings and mourning in the family. The purpose of this paper is to systematise the existing individual theoretical notions and to integrate them in thematic units. The survey of basic conclusions should enable a better understanding of the importance and role of the family in the care for the dying, and a more efficient planning and provision of the necessary professional help and support

ASPECTS OF GOOD DEATH

Iako su umiranje i smrt postali zasebna znanstvena tema, još uvijek se nedovoljno zna o tome kako kvalitetno živjeti do samog kraja. Mnoge odgovore o ovom području daje palijativna skrb – skrb o umirućima i njihovim obiteljima. Ona se posvećuje stvaranju okolnosti u kojima smrt postaje prihvatljiva i dostojanstvena pa na taj način promovira koncept »dobra smrt«. Postojeći domaći i strani prikazi dobre smrti kod neizlječivo bolesnih osoba su fragmentarni i nedostaje im integrativni pristup. Svrha je ovog rada, pregledom recentnih teorijskih spoznaja, objediniti pojedinačne prikaze u cjelinu te sustavno i analitički opisati aspekte dobre smrti. Predstavljene spoznaje ukazuju da je dobra smrt temeljno ljudsko pravo i vrijednost te dinamička i humanistička kategorija što odražava jedinstveno iskustvo umirućeg. Izrazito je socijalni događaj i potpuno se može ostvariti jedino unutar socijalnog okruženja i odnosa s drugim ljudima. Neki njeni najpoželjniji aspekti su: prirodnost, kvaliteta življenja, upravljanje simptomima, boli i osjećajima, osobne vrijednosti, socijalna podrška, humanost i dostojanstvo, duhovnost i skrb o obitelji.Although death and dying became a separate scientific topic, the knowledge about living a life of quality until the very end is still insufficient. Palliative care – the care about the dying and their families - provides many answers in this area. It is dedicated to creating the circumstances in which death becomes acceptable and dignified, thus promoting the concept of good death. The existing national and international reviews of good death in terminally ill persons are fragmentary and lack an integrative approach. The purpose of this paper is to integrate the individual reviews into a whole through the survey of recent theoretical notions, and to systematically and analytically describe the aspects of good death. Presented notions point out that good death is a fundamental human right and value, as well as a dynamic and humanistic category which reflects the unique experience of the dying person. It is a markedly social event, and can be fully realised only within the social environment and through relationships with other people. Some of its most desirable aspects are: naturalness, quality of life, managing symptoms, pain and feelings, personal values, social support, humanity and dignity, spirituality and care about the family

Tunable coupling to a mechanical oscillator circuit using a coherent feedback network

We demonstrate a fully cryogenic microwave feedback network composed of modular superconducting devices connected by transmission lines and designed to control a mechanical oscillator coupled to one of the devices. The network features an electromechanical device and a tunable controller that coherently receives, processes and feeds back continuous microwave signals that modify the dynamics and readout of the mechanical state. While previous electromechanical systems represent some compromise between efficient control and efficient readout of the mechanical state, as set by the electromagnetic decay rate, the tunable controller produces a closed-loop network that can be dynamically and continuously tuned between both extremes much faster than the mechanical response time. We demonstrate that the microwave decay rate may be modulated by at least a factor of 10 at a rate greater than $10^4$ times the mechanical response rate. The system is easy to build and suggests that some useful functions may arise most naturally at the network-level of modular, quantum electromagnetic devices.Comment: 11 pages, 6 figures, final published versio