Quantum spin systems are by now known to exhibit a large number of different classes of spin liquid phases. By contrast, for classical Heisenberg models, only one kind of fractionalized spin liquid ...phase, the so-called Coulomb or U(1) spin liquid, has until recently been identified: This exhibits algebraic spin correlations and impurity moments, "orphan spins," whose size is a fraction of that of the underlying microscopic degrees of freedom. Here, we present two Heisenberg models exhibiting fractionalization in combination with exponentially decaying correlations. These can be thought of as a classical continuous spin version of a Z_{2} spin liquid. Our work suggests a systematic search and classification of classical spin liquids as a worthwhile endeavor.
The formulation of a complete theory of classical electromagnetism by Maxwell is one of the milestones of science. The capacity of many-body systems to provide emergent mini-universes with vacua ...quite distinct from the one we inhabit was only recognized much later. Here, we provide an account of how simple systems of localized spins manage to emulate Maxwell electromagnetism in their low-energy behaviour. They are much less constrained by symmetry considerations than the relativistically invariant electromagnetic vacuum, as their substrate provides a non-relativistic background with even translational invariance broken. They can exhibit rich behaviour not encountered in conventional electromagnetism. This includes the existence of magnetic monopole excitations arising from fractionalization of magnetic dipoles; as well as the capacity of disorder, by generating defects on the lattice scale, to produce novel physics, as exemplified by topological spin glassiness or random Coulomb magnetism.
This article is part of the themed issue ‘Unifying physics and technology in light of Maxwell's equations’.
We show that the honeycomb Heisenberg antiferromagnet with J_{1}/2=J_{2}=J_{3}, where J_{1}, J_{2}, and J_{3} are first-, second-, and third-neighbor couplings, respectively, forms a classical spin ...liquid with pinch-point singularities in the structure factor at the Brillouin zone corners. Upon dilution with nonmagnetic ions, fractionalized degrees of freedom carrying 1/3 of the free moment emerge. Their effective description in the limit of low temperature is that of spins randomly located on a triangular lattice, with a frustrated sublattice-sensitive interaction of long-ranged logarithmic form. The XY version of this magnet exhibits nematic thermal order by disorder. This comes with a clear experimental diagnostic in neutron scattering, which turns out to apply also to the case of the celebrated planar order by disorder of the kagome Heisenberg antiferromagnet.
We study spin glass behavior in a random Ising Coulomb antiferromagnet in two and three dimensions using Monte Carlo simulations. In two dimensions, we find a transition at zero temperature with ...critical exponents consistent with those of the Edwards-Anderson model, though with large uncertainties. In three dimensions, evidence for a finite-temperature transition, as occurs in the Edwards-Anderson model, is rather weak. This may indicate that the sizes are too small to probe the asymptotic critical behavior, or possibly that the universality class is different from that of the Edwards-Anderson model and has a lower critical dimension equal to three.
As part of the built environment objects and interior design features can affect thoughts, emotions and behaviour in various ways. Referring to the concept of material and conceptual priming (Kay et ...al., 2004; Berger & Fitzsimons, 2008), these objects can provoke associations and by that subconsciously activate mental concepts which influence emotional states, judgements and subsequent behaviours. In many healthcare facilities, the formal-aesthetic design of the built environment visually conveys the concept of institutionalisation through clinical and sterile styles, impersonal and standardised configurations and a lack of individualisation. This applies in particular to the setting of psychiatric facilities in which from a clinical point of view sterile and impersonal aesthetics are not required and might even be detrimental to the therapeutic processes. However, there is reason to believe that the use of everyday objects can support therapeutic processes and thus be seen as an element of psychosocially supportive design (Ulrich, 1997) in two ways. Firstly, everyday objects derived from domestic contexts refer to aesthetics that are contrary to the concept of institutionalisation. Instead by communicating features of comfort and subtle luxury they might activate the mental concept of valorisation which can be seen as an important resource in therapeutic settings that strengthens commitment and trusts. Secondly, offering choice of a variety of everyday objects in psychiatric settings enables patients to exert control in a context that otherwise is characterised by total loss of control. This increased sense of control is an important part of Antonovsky's sense of coherence (1979) and a valuable asset for recovery and empowerment of psychiatric patients.
Health behaviour is a crucial aspect regarding overall health and well-being. However, the role of aesthetics and the built environment in relation to this is often neglected. Disciplines such as ...consumer psychology use aesthetic features of objects and environments such as colour, lighting and haptic structures to increase sales, customer loyalty and brand awareness in various contexts. In many cases these designs prime a certain mental concept to influence subsequent thoughts, feelings and behaviours. While there is a growing body of literature regarding the profound effect these design decisions can have from a consumer perspective, this knowledge is hardly used in the context of health promotion. In contrary, in settings such as schools, universities and hospitals, the built environment does prime specific mental concepts however often randomly and without designers being aware of it. In a series of experiments in (a) a university (n = 83) and (b) a clinical context (n = 36), participants were confronted with primes (positive vs. negative) in the shape of lecterns that were supposed to prime health related mental concepts such as sense of control and health-related behaviour. In the clinical context participants confronted with positive primes mentioned significantly more sport-related words in an association task. Furthermore, the primes seem to influence whether participants choose healthy vs. unhealthy rewards after the task. In the university setting, for some resiliency related items (e.g. motivation regarding planned behaviour) students answered significantly more positively standing at the lectern resembling the positive prime. Although, only mild effects could be found, these results indicate that objects and interiors might influence health behaviour by priming certain mental concepts. More research is needed especially on the role of duration, intensity and extent of the design intervention for using objects to prime health behaviour change.
Key messages
The design of the built environment can be seen as a prime that might influence health behaviour change.
In the context of public health, evidence-based and research driven design can be an effective tool for health behaviour interventions.
Abstract
After the brief initial input presentations outlining relevant aspects such as the eco-psychosocial approach as well as facts regarding the context of the case study Crete, a co-creative ...multidisciplinary workshop is being facilitated that aims at developing concepts for early mental health prevention and treatment focusing on innovations in the built environment.
Touchpoint inventory for urban public mental health offerings
The key methodology of the workshop follows principles from experience design (Risbon et al., 2018) and service design (Stickdom et al., 2018) using the touchpoint inventory. The overall workshop is divided into two main phases. In the first phase participants will be divided into two groups. One of them will outline a chronological journey for early mental health interventions for stereotypical mentally ill person (e.g. preventive information, low threshold support groups, and so on). The second group will collect places and elements of the built environment that surf as a basis for interaction (”channels”) by which services for mental healthcare and prevention can be submitted (e.g. Shops, public places, coffee shops, libraries etc.).
In the second phase, results of both groups will be collected using a spreadsheet. All participants are then asked to ideate concepts for “touchpoints” at the intersection of both groups of elements. These concepts can serve as a conceptual starting point for more comprehensive developments on design for early mental health interventions.
References
Risdon, C., Quattlebaum, P., Rettig, M. (2018) Orchestrating experiences. Collaborative design for complexity. Brooklyn, New York: Rosenfeld Media
Stickdorn, M., Hormess, M., Lawrence, A., Schneider, J. (Hg.) (2018) This is service design doing. Applying service design thinking in the real world; a practitioners` handbook. First edition. Sebastapol, CA: O'Reilly
The formulation of a complete theory of classical electromagnetism by Maxwell is one of the milestones of science. The capacity of many-body systems to provide emergent mini-universes with vacua ...quite distinct from the one we inhabit was only recognized much later. Here, we provide an account of how simple systems of localized spins manage to emulate Maxwell electromagnetism in their low-energy behaviour. They are much less constrained by symmetry considerations than the relativistically invariant electromagnetic vacuum, as their substrate provides a non-relativistic background with even translational invariance broken. They can exhibit rich behaviour not encountered in conventional electromagnetism. This includes the existence of magnetic monopole excitations arising from fractionalization of magnetic dipoles; as well as the capacity of disorder, by generating defects on the lattice scale, to produce novel physics, as exemplified by topological spin glassiness or random Coulomb magnetism. This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'.
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