Hidden Phases Research Articles

Engineering of Electromechanical Oxides by Symmetry Breaking

AbstractComplex oxides exhibit a wide range of fascinating functionalities, such as ferroelectricity, piezoelectricity, and pyroelectricity, which are indispensable for cutting‐edge electronics, energy, and information technologies. The intriguing physical properties of these complex oxides arise from the complex interplay between lattice, orbital, charge, and spin degrees of freedom. Here, it is reviewed how electromechanical properties can be achieved/improved by artificially breaking the symmetry of centrosymmetric oxides via engineering thermodynamic variables such as stress, strain, electric field, and chemical potentials. The mechanisms that have been utilized to break the inherent symmetry of conventional materials that lead to novel functionalities and applications are explored. It is highlighted that access to “hidden phases,” which otherwise are prohibited, could uncover opportunities to host exotic properties, such as piezoelectricity, pyroelectricity, etc. This review not only reports how to engineer intrinsically nonpolar and centrosymmetric oxides for emergent properties, but also has implications for manipulating polar functional materials for better performance.

Cluster Toroidal Multipoles Formed by Electric-Quadrupole and Magnetic-Octupole Trimers: A Possible Scenario for Hidden Orders in Ca5Ir3O12

Cluster multipole orderings composed of atomic high-rank multipole moments are theoretically investigated with a 5$d$-electron compound Ca$_5$Ir$_3$O$_{12}$ in mind. Ca$_5$Ir$_3$O$_{12}$ exhibits two hidden orders: One is an intermediate-temperature phase with time-reversal symmetry and the other is a low-temperature phase without time-reversal symmetry. By performing the symmetry and augmented multipole analyses for a $d$-orbital model under the hexagonal point group $D_{\rm 3h}$, we find that the 120$^{\circ}$-type ordering of the electric quadrupole corresponds to cluster electric toroidal dipole ordering with the electric ferroaxial moment, which can become the microscopic origin of the intermediate-temperature phase in Ca$_5$Ir$_3$O$_{12}$. Furthermore, based on ${}^{193}$Ir synchrotron-radiation-based M\"{o}ssbauer spectroscopy, we propose that the low-temperature phase in Ca$_5$Ir$_3$O$_{12}$ is regarded as a coexisting state with cluster electric toroidal dipole and cluster magnetic toroidal quadrupole, the latter of which is formed by the 120$^{\circ}$-type ordering of the magnetic octupole and accompanies a small uniform magnetization as a secondary effect. Our results provide a clue to two hidden phases in Ca$_5$Ir$_3$O$_{12}$.

“Hearing” ahead of the sound: How musicians listen via proprioception and seen gestures in performance

ABSTRACT This article addresses the peculiar temporal challenges that musicians face in performance and its implications for perception. In a performance, there is routinely no time out, no possibility of stopping and redoing. Players have to “hear” before notes sound, so they can organize their bodies to fit in. My analysis identifies three strategies that players adopt to take the load off their ear. Players listen via the seen gestures of others that signify what should be heard/played. They hear the music by feeling the rhythmic pulse. Lastly, they hear ahead through their proprioceptive sense of how they are organizing their bodies to make a sound. These observations show how players’ sense of their sound, crucial to the achievement of social order in performance, is achieved through largely hidden phases that organize hearing in relation to what we typically conceptualize as other sensory modalities.

Toward nonthermal control of excited quantum materials: framework and investigations by ultrafast electron scattering and imaging

Quantum material systems upon applying ultrashort laser pulses provide a rich platform to access excited material phases and their transformations that are not entirely like their equilibrium counterparts. The addressability and potential controls of metastable or long-trapped out-of-equilibrium phases have motivated interests both for the purposes of understanding the nonequilibrium physics and advancing the quantum technologies. Thus far, the dynamical spectroscopic probes eminently focus on microscopic electronic and phonon responses. For characterizing the long-range dynamics, such as order parameter fields and fluctuation effects, the ultrafast scattering probes offer direct sensitivity. Bridging the connections between the microscopic dynamics and macroscopic responses is central toward establishing the nonequilibrium physics behind the light-induced phases. Here, we present a path toward such understanding by cross-examining the structure factors associated with different dynamical states obtained from ultrafast electrons scattering, imaging, and modeling. We give the basic theoretical framework on describing the non-equilibrium scattering problems and briefly describe how such framework relates to the out-of-equilibrium phenomena. We give effective models outlining the emergences of nonthermal critical points, hidden phases, and non-equilibrium relaxational responses from vacuum-suspended rare?earth tritellurides, tantalum disulfides thin films, and vanadium dioxide nanocrystalline materials upon light excitations.

Hidden phases born of a quantum spin liquid: Application to pyrochlore spin ice

Quantum spin liquids (QSL) have generated considerable excitement as phases of matter with emergent gauge structures and fractionalized excitations. In this context, phase transitions out of QSLs have been widely discussed as Higgs transitions from deconfined to confined phases of a lattice gauge theory. However the possibility of a wider range of novel phases, occuring between these two limits, has yet to be systematically explored. In this Letter, we develop a formalism which allows for interactions between fractionalised quasiparticles coming from the constraint on the physical Hilbert space, and can be used to search for exotic, hidden phases. Taking pyrochlore spin ice as a starting point, we show how a U(1) QSL can give birth to abundant daughter phases, without need for fine--tuning of parameters. These include a (charged--) $\mathbb{Z}_2$ QSL, and a supersolid. We discuss implications for experiment, and numerical results which support our analysis. These results are of broad relevance to QSL subject to a parton description, and offer a new perspective for searching exotic hidden phases in quantum magnets.

Hidden phases of de-Europeanization: insights from historical institutionalism

ABSTRACT While the EU’s impact on member and non-member states has been well researched, we have much less understanding of how Europeanization processes give way to de-Europeanization, a widespread phenomenon of the past decade. This paper unpacks and explores the hidden phases and modes of de-Europeanization. I argue that the models of gradual institutional change in historical institutionalism, namely ‘layering’, ‘conversion’ and ‘drift’, operate in different phases of de-Europeanization in a sequential mode. I explore this argument empirically in the domain of regional development policy in Turkey, the longest-standing candidate country. The empirical analysis shows that the mode of ‘layering’, which involves the addition of new rules without upsetting the existing arrangements, during Europeanization unleashed a subsequent mode of ‘conversion’, in which new rules were upheld but exploited in implementation. This phase was then followed by ‘drift’, in which new rules have become irrelevant in the midst of changing circumstances.

Pap’s Image Analysis and Development on Cervical Cancer Screening Process

In around the globe, harmful cervical development is 2nd main sickness impacted by a woman. Cervical harmful development is the critical purpose of women's death. Inferable from cervix harmful development, transcendent of passing interminably is happening in less defoliated districts of the world. The basic objective of this manuscript, to handle strategic distance from and fix the cervical threat using PST. At whatever point found at hidden phases, in this sort of illness might be completely diminished. At the starting time, the Pap smear test (PST) is a fundamental imparted system for distinguishing harmful cervical development. This manuscript provides a review of cervical harmful development and assessment of the unmistakable frameworks. Fitting methodologies have been utilized to orchestrate the smear picture as ordinary/bizarre using the apparent goals. Such recuperation utilized to find PS cells and takes the most ideal treatment by then decrease dangerous cervical development. This issue closeness thick to get to precise treatment, screening, and continuation organizations.

Atomically Resolved Edge States on a Layered Ferroelectric Oxide.

The emerging surface/edge electronic phases driven by broken symmetry effects have attracted great attention in low-dimensional electronic systems. However, experimental proof on their existence in ferroelectric oxides at the atomic scale is still missing. In this work, metallic surface states are observed on layered Bi2WO6 by scanning tunneling microscopy/spectroscopy. Differential conductance is remarkably enhanced near the step edge compared with that on the terrace, forming a one-dimensional edge state. Density functional theory calculations verify that symmetry breaking at the surface determines the electronic structures and O 2p orbitals contribute the most to the density of states around the Fermi level. Our discovery provides a new strategy toward the hidden phases on other correlated oxide surfaces.

First Hitting Times to Intermittent Targets.

In noisy environments such as the cell, many processes involve target sites that are often hidden or inactive, and thus not always available for reaction with diffusing entities. To understand reaction kinetics in these situations, we study the first hitting time statistics of a one-dimensional Brownian particle searching for a target site that switches stochastically between visible and hidden phases. At high crypticity, an unexpected rate limited power-law regime emerges for the first hitting time density, which markedly differs from the classic t^{-3/2} scaling for steady targets. Our problem admits an asymptotic mapping onto a mixed, or Robin, boundary condition. Similar results are obtained with non-Markov targets and particles diffusing anomalously.

Terahertz field-induced ferroelectricity in quantum paraelectric SrTiO3.

"Hidden phases" are metastable collective states of matter that are typically not accessible on equilibrium phase diagrams. These phases can host exotic properties in otherwise conventional materials and hence may enable novel functionality and applications, but their discovery and access are still in early stages. Using intense terahertz electric field excitation, we found that an ultrafast phase transition into a hidden ferroelectric phase can be dynamically induced in quantum paraelectric strontium titanate (SrTiO3). The induced lowering in crystal symmetry yields substantial changes in the phonon excitation spectra. Our results demonstrate collective coherent control over material structure, in which a single-cycle field drives ions along the microscopic pathway leading directly to their locations in a new crystalline phase on an ultrafast time scale.

Driving strontium titanate ferroelectric

Physics Hidden phases are metastable collective states of matter that are typically not accessible on equilibrium phase diagrams. Nova et al. used infrared pulses to excite higher-frequency lattice modes that drive the crystal into a metastable ferroelectric phase, a phase that can persist for many hours. X. Li et al. used terahertz fields to drive the soft mode that moves the ions in the crystal into the positions they occupy in the new phase. The ferroelectric phase in this case was transient, lasting on the order of 10 picoseconds. Because these hidden phases can host exotic properties in otherwise conventional materials, the accessibility to and control of such hidden phases may broaden potential functionality and applications. Science , this issue p. [1075][1], p. [1079][2] [1]: /lookup/doi/10.1126/science.aaw4911 [2]: /lookup/doi/10.1126/science.aaw4913

Metastable ferroelectricity in optically strained SrTiO3.

Fluctuating orders in solids are generally considered high-temperature precursors of broken symmetry phases. However, in some cases, these fluctuations persist to zero temperature and prevent the emergence of long-range order. Strontium titanate (SrTiO3) is a quantum paraelectric in which dipolar fluctuations grow upon cooling, although a long-range ferroelectric order never sets in. Here, we show that optical excitation of lattice vibrations can induce polar order. This metastable polar phase, observed up to temperatures exceeding 290 kelvin, persists for hours after the optical pump is interrupted. Furthermore, hardening of a low-frequency vibration points to a photoinduced ferroelectric phase transition, with a spatial domain distribution suggestive of a photoflexoelectric coupling.

Exploration of metastability and hidden phases in correlated electron crystals visualized by femtosecond optical doping and electron crystallography.

Characterizing and understanding the emergence of multiple macroscopically ordered electronic phases through subtle tuning of temperature, pressure, and chemical doping has been a long-standing central issue for complex materials research. We report the first comprehensive studies of optical doping-induced emergence of stable phases and metastable hidden phases visualized in situ by femtosecond electron crystallography. The electronic phase transitions are triggered by femtosecond infrared pulses, and a temperature-optical density phase diagram is constructed and substantiated with the dynamics of metastable states, highlighting the cooperation and competition through which the macroscopic quantum orders emerge. These results elucidate key pathways of femtosecond electronic switching phenomena and provide an important new avenue to comprehensively investigate optical doping-induced transition states and phase diagrams of complex materials with wide-ranging applications.

Managing river flow in arid regions with matrix analytic methods

Matrix analytic methods (MAM) support non-geometric transitions between sets of states, termed levels, by introducing states, known as phases, within levels. The phases can correspond to an observed variable or they can be hidden. MAM models have been extensively used in telecommunications, and efficient algorithms for evaluation of performance continue to be developed. Following a review of MAM in discrete time, the daily flows of the ephemeral Cooper Creek, in South Australia, are modelled. Hidden phases are used in the distribution of the duration of the dry spells, whereas observed phases, are used within non-zero flow levels. Seasonal and non-seasonal models are compared. A second application is managing the level of a reservoir in Queensland, using MAM within stochastic dynamic programming. Inflows to the reservoir are seasonal and influenced by the value of the Southern Oscillation Index (SOI), which is used to define phases. The benefit of including SOI in the decision process is shown.

Estimation of the Biphasic Property in a Female’s Menstrual Cycle from Cutaneous Temperature Measured During Sleep

This paper proposes a method to estimate a woman's menstrual cycle based on the hidden Markov model (HMM). A tiny device was developed that attaches around the abdominal region to measure cutaneous temperature at 10-min intervals during sleep. The measured temperature data were encoded as a two-dimensional image (QR code, i.e., quick response code) and displayed in the LCD window of the device. A mobile phone captured the QR code image, decoded the information and transmitted the data to a database server. The collected data were analyzed by three steps to estimate the biphasic temperature property in a menstrual cycle. The key step was an HMM-based step between preprocessing and postprocessing. A discrete Markov model, with two hidden phases, was assumed to represent higher- and lower-temperature phases during a menstrual cycle. The proposed method was verified by the data collected from 30 female participants, aged from 14 to 46, over six consecutive months. By comparing the estimated results with individual records from the participants, 71.6% of 190 menstrual cycles were correctly estimated. The sensitivity and positive predictability were 91.8 and 96.6%, respectively. This objective evaluation provides a promising approach for managing premenstrual syndrome and birth control.