Detection of entanglement between collective spins

Entanglement between individual spins can be detected by using thermodynamics quantities as entanglement witnesses. This applies to collective spins also, provided that their internal degrees of freedom are frozen, as in the limit of weakly-coupled nanomagnets. Here, we extend such approach to the detection of entanglement between subsystems of a spin cluster, beyond such weak-coupling limit. The resulting inequalities are violated in spin clusters with different geometries, thus allowing the detection of zero- and finite-temperature entanglement. Under relevant and experimentally verifiable conditions, all the required expectation values can be traced back to correlation functions of individual spins, that are now made selectively available by four-dimensional inelastic neutron scattering

Procedures for the interpretation and use of elevation scanning laser/multi-sensor data for short range hazard detection and avoidance for an autonomous planetary rover

An autonomous roving science vehicle that relies on terrain data acquired by a hierarchy of sensors for navigation was one method of carrying out such a mission. The hierarchy of sensors included a short range sensor with sufficient resolution to detect every possible obstacle and with the ability to make fast and reliable terrain characterizations. A multilaser, multidetector triangulation system was proposed as a short range sensor. The general system was studied to determine its perception capabilities and limitations. A specific rover and low resolution sensor system was then considered. After studying the data obtained, a hazard detection algorithm was developed that accounts for all possible terrains given the sensor resolution. Computer simulation of the rover on various terrains was used to test the entire hazard detection system

Tolerance in the Peer Review of Interdisciplinary Research in Architectural Journal Publishing

In order to consider how to negotiate the publication space of interdisciplinary research in architecture in academic journals, this essay reflects on the current forms of writing in architectural discourse, the history of a “critique militante” architectural (peer) review process within the academy, and the future possibilities of a feminist oriented process that seeks to accommodate otherness. These reflections emerge from our experience as academics and as women editors of the interdisciplinary, multimedia journal, Architecture and Culture, first published in 2013. The essay argues that peer review for interdisciplinary research in architecture needs to be re-negotiated as publishing tolerance through a contingency approach to evaluation. We conclude that academic architectural journal publishing can flourish through broader conversational modes of open, non-hierarchical knowledge exchange and editorial practice where published work undergoes a process of becoming

Quantum-gate implementation in permanently coupled AF spin rings without need of local fields

We propose a scheme for the implementation of quantum gates which is based on the qubit encoding in antiferromagnetic molecular rings. We show that a proper engineering of the intercluster link would result in an effective coupling that vanishes as far as the system is kept in the computational space, while it is turned on by a selective excitation of specific auxiliary states. These are also shown to allow the performing of single- and two-qubit gates without an individual addressing of the rings by means of local magnetic fields.Comment: To appear in Physical Review Letter

Tolerance in the Peer Review of Interdisciplinary Research in Architectural Journal Publishing

In order to consider how to negotiate the publication space of interdisciplinary research in architecture in academic journals, this essay reflects on the current forms of writing in architectural discourse, the history of a “critique militante” architectural (peer) review process within the academy, and the future possibilities of a feminist oriented process that seeks to accommodate otherness. These reflections emerge from our experience as academics and as women editors of the interdisciplinary, multimedia journal, Architecture and Culture, first published in 2013. The essay argues that peer review for interdisciplinary research in architecture needs to be re-negotiated as publishing tolerance through a contingency approach to evaluation. We conclude that academic architectural journal publishing can flourish through broader conversational modes of open, non-hierarchical knowledge exchange and editorial practice where published work undergoes a process of becoming

Geomorphology of the lower Mesopotamian plain at Tell Zurghul archaeological site

The landscape of the Lower Mesopotamia Plain (LMP) has been moulded by water-related processes, consequently, its Holocene geomorphic evolution has been strictly connected to the fluvial process and the anthropogenic water management since 8000 BC. About 6000 years ago, during the maximum marine ingression, the modern cities of Nasiriyah and Al-Amara were close to the Persian Gulf shoreline. Successively, the Tigris and Euphrates developed two wide delta systems, that prograded south-eastward developing a complex fluvial network. Remote sensing investigations over the LMP using satellite imagery and topographic analysis revealed the surficial expression of deltaic bodies with a lobate planform and several terminal distributary channels (TDCs), classifiable as tidal-influenced river-dominated deltas. Tell Zurghul archaeological site, belonging to the ancient State of Lagash, expanded in the western part of the recognized TDC during the Mid- and Late Holocene. Indeed, the occurrence of a divergent multi-channel system supplied water for the early civilizations, which improved the water management and prevented floods through a canals network. Therefore, the multi-sensor remote sensing approach over an area of 2850 km2 allowed us to recognize several fluvial landforms, both still active and relict, attributable to the Holocene riverscape of the LMP, as well as anthropogenic features and aeolian deposits. The Main map is a geomorphological map at the scale of 1:120,000 centred on Tell Zurghul, focusing on the geometry, spatial distribution, and state of activity of erosional and constructional landforms

Zaha Hadid's penthouse: Gender, creativity and 'biopolitics' in the neoliberal workplace

This chapter studies and critically examines the practice space inside and outside Zaha Hadid’s penthouse apartment and discusses how her gender, the marketing of her creativity, and her designs can affect architecture’s starchitect “biopolitic.” It presents the story of Hadid’s penthouse in the context of Margaret Thatcher’s neoliberalism and refers to writings on the impact of neoliberalism generally, by Michel Foucault and Wendy Brown, to discuss how architectural production, at the corporate level, ties the body of the architect to an incessant drive for increased marketization through the concept of homo oeconomicus. The chapter argues that the economic man architects and economic woman architects who perform a singularly focused “masculinist” form of labor, where work is everything, need to be understood and challenged as idealist practice in the profession. The chapter urges architectural practitioners to value their self as enterprise, not the enterprise of their self

Calculation of pure dephasing for excitons in quantum dots

Pure dephasing of an exciton in a small quantum dot by optical and acoustic phonons is calculated using the ``independent boson model''. Considering the case of zero temperature the dephasing is shown to be only partial which manifests itself in the polarization decaying to a finite value. Typical dephasing times can be assigned even though the spectra exhibits strongly non-Lorentzian line shapes. We show that the dephasing from LO phonon scattering, occurs on a much larger time scale than that of dephasing due to acoustic phonons which for low temperatures are also a more efficient dephasing mechanism. The typical dephasing time is shown to strongly depend on the quantum dot size whereas the electron phonon ``coupling strength'' and external electric fields tend mostly to effect the residual coherence. The relevance of the dephasing times for current quantum information processing implementation schemes in quantum dots is discussed

Spin electric effects in molecular antiferromagnets

Molecular nanomagnets show clear signatures of coherent behavior and have a wide variety of effective low-energy spin Hamiltonians suitable for encoding qubits and implementing spin-based quantum information processing. At the nanoscale, the preferred mechanism for control of quantum systems is through application of electric fields, which are strong, can be locally applied, and rapidly switched. In this work, we provide the theoretical tools for the search for single molecule magnets suitable for electric control. By group-theoretical symmetry analysis we find that the spin-electric coupling in triangular molecules is governed by the modification of the exchange interaction, and is possible even in the absence of spin-orbit coupling. In pentagonal molecules the spin-electric coupling can exist only in the presence of spin-orbit interaction. This kind of coupling is allowed for both $s=1/2$ and $s=3/2$ spins at the magnetic centers. Within the Hubbard model, we find a relation between the spin-electric coupling and the properties of the chemical bonds in a molecule, suggesting that the best candidates for strong spin-electric coupling are molecules with nearly degenerate bond orbitals. We also investigate the possible experimental signatures of spin-electric coupling in nuclear magnetic resonance and electron spin resonance spectroscopy, as well as in the thermodynamic measurements of magnetization, electric polarization, and specific heat of the molecules.Comment: 31 pages, 24 figure