scholarly journals Multi-fixed point numerical conformal bootstrap: a case study with structured global symmetry

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Matthew T. Dowens ◽  
Chris A. Hooley
Keyword(s):  
Group Symmetry ◽  
Global Symmetry ◽  
Minimal Set ◽  
Conformal Field ◽  
Conformal Bootstrap ◽  
Critical Theories ◽  
Global Symmetry Group ◽  
Starting Point ◽  
Future Utility

Abstract In large part, the future utility of modern numerical conformal bootstrap depends on its ability to accurately predict the existence of hitherto unknown non-trivial conformal field theories (CFTs). Here we investigate the extent to which this is possible in the case where the global symmetry group has a product structure. We do this by testing for signatures of fixed points using a mixed-correlator bootstrap calculation with a minimal set of input assumptions. This ‘semi-blind’ approach contrasts with other approaches for probing more complicated groups, which ‘target’ known theories with additional spectral assumptions or use the saturation of the single-correlator bootstrap bound as a starting point. As a case study, we select the space of CFTs with product-group symmetry O(15) ⊗ O(3) in d = 3 dimensions. On the assumption that there is only one relevant scalar (ℓ = 0) singlet operator in the theory, we find a single ‘allowed’ region in our chosen space of scaling dimensions. The scaling dimensions corresponding to two known large-N critical theories, the Heisenberg and the chiral ones, lie on or very near the boundary of this region. The large-N antichiral point lies well outside the ‘allowed’ region, which is consistent with the expectation that the antichiral theory is unstable, and thus has an additional relevant scalar singlet operator. We also find a sharp kink in the boundary of the ‘allowed’ region at values of the scaling dimensions that do not correspond to the (N, M ) = (3, 15) instance of any large-N -predicted O(N ) ⊗ O(M ) critical theory.

scholarly journals Perturbative and nonperturbative studies of CFTs with MN global symmetry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Johan Henriksson ◽  
Andreas Stergiou
Keyword(s):  
Fixed Points ◽  
Numerical Data ◽  
Three Dimensions ◽  
Global Symmetry ◽  
Conformal Field Theories ◽  
Conformal Field ◽  
Conformal Bootstrap ◽  
State Of Affairs ◽  
Perturbative Limit ◽  
Good Agreement

Fixed points in three dimensions described by conformal field theories with \ensuremath{M N}_{m,n} = O(m)^n\rtimes S_nMNm,n=O(m)n⋊Sn global symmetry have extensive applications in critical phenomena. Associated experimental data for m=n=2m=n=2 suggest the existence of two non-trivial fixed points, while the \varepsilonε expansion predicts only one, resulting in a puzzling state of affairs. A recent numerical conformal bootstrap study has found two kinks for small values of the parameters mm and nn, with critical exponents in good agreement with experimental determinations in the m=n=2m=n=2 case. In this paper we investigate the fate of the corresponding fixed points as we vary the parameters mm and nn. We find that one family of kinks approaches a perturbative limit as mm increases, and using large spin perturbation theory we construct a large mm expansion that fits well with the numerical data. This new expansion, akin to the large NN expansion of critical O(N)O(N) models, is compatible with the fixed point found in the \varepsilonε expansion. For the other family of kinks, we find that it persists only for n=2n=2, where for large mm it approaches a non-perturbative limit with \Delta_\phi\approx 0.75Δϕ≈0.75. We investigate the spectrum in the case \ensuremath{M N}_{100,2}MN100,2 and find consistency with expectations from the lightcone bootstrap.

scholarly journals Bootstrapping mixed correlators in three-dimensional cubic theories II

2020 ◽  
Vol 8 (6) ◽  
Author(s):  
Stefanos R. Kousvos ◽  
Andreas Stergiou
Keyword(s):  
Condensed Matter ◽  
Three Dimensional ◽  
Global Symmetry ◽  
Energy Tensor ◽  
Conformal Field Theories ◽  
Cubic Symmetry ◽  
Conformal Field ◽  
Conformal Bootstrap ◽  
Perturbative Methods ◽  
Stress Energy

Conformal field theories (CFTs) with cubic global symmetry in 3D are relevant in a variety of condensed matter systems and have been studied extensively with the use of perturbative methods like the \varepsilonε expansion. In an earlier work, we used the nonperturbative numerical conformal bootstrap to provide evidence for the existence of a previously unknown 3D CFT with cubic symmetry, dubbed “Platonic CFT”. In this work, we make further use of the numerical conformal bootstrap to perform a three-dimensional scan in the space of scaling dimensions of three low-lying operators. We find a three-dimensional isolated allowed region in parameter space, which includes both the 3D (decoupled) Ising model and the Platonic CFT. The essential assumptions on the spectrum of operators used to provide the isolated allowed region include the existence of a stress-energy tensor and the irrelevance of certain operators (in the renormalization group sense).

Ein rechtsfreier Raum? Die legale Situation auf den Färöern im Spiegel der ‚Færeyinga saga‘

2020 ◽  
Vol 25 (1) ◽  
pp. 30-45
Author(s):  
Andreas Schmidt
Keyword(s):  
Cultural Norms ◽  
Old Icelandic ◽  
Power Politics ◽  
Starting Point ◽  
Narrative Literature ◽  
The Law

AbstractThe chapter argues for a more nuanced and empirically based understanding of the discourse on law and socio-cultural norms in Old Icelandic literature on the grounds of a narratological reading of ‘Færeyinga saga’ as a case study. It has often been claimed that Icelandic sources express an ideal of freedom based on communality as guaranteed by the law. By contrast, ‘Færeyinga saga’ represents a cynical discourse on power politics that renders law as an invariable concept obsolete and works solely on the principle that ‘might is right’. This cynicism, however, is presented in a form that leaves the narrative open to interpretation, showing that regardless of its possible dating, narrative literature can serve as a starting point for social discussion. Consequently, the discourse on law in medieval Iceland must be perceived as more polyphonic than has been allowed for by previous unifying readings in scholarship.

scholarly journals Parafermionization, bosonization, and critical parafermionic theories

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Yuan Yao ◽  
Akira Furusaki
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
Degrees Of Freedom ◽  
Lattice Models ◽  
Partition Functions ◽  
Minimal Models ◽  
Fermionic Model ◽  
Conformal Field ◽  
Critical Theories ◽  
Wigner Transformation

AbstractWe formulate a ℤk-parafermionization/bosonization scheme for one-dimensional lattice models and field theories on a torus, starting from a generalized Jordan-Wigner transformation on a lattice, which extends the Majorana-Ising duality atk= 2. The ℤk-parafermionization enables us to investigate the critical theories of parafermionic chains whose fundamental degrees of freedom are parafermionic, and we find that their criticality cannot be described by any existing conformal field theory. The modular transformations of these parafermionic low-energy critical theories as general consistency conditions are found to be unconventional in that their partition functions on a torus transform differently from any conformal field theory whenk >2. Explicit forms of partition functions are obtained by the developed parafermionization for a large class of critical ℤk-parafermionic chains, whose operator contents are intrinsically distinct from any bosonic or fermionic model in terms of conformal spins and statistics. We also use the parafermionization to exhaust all the ℤk-parafermionic minimal models, complementing earlier works on fermionic cases.

‘More Product, Less Process’ (MPLP): An early printed book project

2021 ◽  
pp. 096100062110267
Author(s):  
Karen Attar
Keyword(s):  
18Th Century ◽  
The United States ◽  
Global Changes ◽  
Main Research ◽  
Advantages And Disadvantages ◽  
Main Research Interest ◽  
Printed Books ◽  
Starting Point ◽  
19Th And 20Th Century

This article addresses the challenge to make printed hidden collections known quickly without sacrificing ultimate quality. It takes as its starting point the archival mantra ‘More product, less process’ and explores its application to printed books, mindful of projects in the United States to catalogue 19th- and 20th-century printed books quickly and cheaply with the help of OCLC. A problem is lack of time or managerial inclination ever to return to ‘quick and dirty’ imports. This article is a case study concerning a collection of 18th-century English imprints, the Graveley Parish Library, at Senate House Library, University of London. Faced with the need to provide metadata as quickly as possible for digitisation purposes, Senate House Library decided, in contrast to its normal treatment of early printed books, to download records from the English Short Title Catalogue and amend them only very minimally before releasing them for public view, and to do this work from catalogue cards rather than the books themselves. The article describes the Graveley Parish collection, the project method’s rationale, and the advantages and disadvantages of sourcing the English Short Title Catalogue for metadata. It discusses the drawbacks of retrospective conversion (cataloguing from cards, not books): insufficient detail in some cases to identify the relevant book, and ignorance of the copy-specific elements of books which can constitute the main research interest. The method is compared against cataloguing similar books from photocopies of title pages, and retrospective conversion using English Short Title Catalogue is compared against retrospective conversion of early printed Continental books from cards using Library Hub Discover or OCLC. The control groups show our method’s effectiveness. The project succeeded by producing records fast that fulfilled their immediate purpose and simultaneously would obviously require revisiting. The uniform nature of the collection enabled the saving of time through global changes.

scholarly journals Bootstrap bounds on closed Einstein manifolds

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
James Bonifacio ◽  
Kurt Hinterbichler
Keyword(s):  
Compact Riemannian Manifold ◽  
Tree Level ◽  
Conformal Field Theories ◽  
Einstein Manifolds ◽  
Consistency Conditions ◽  
Conformal Field ◽  
Geometric Data ◽  
Conformal Bootstrap ◽  
Laplacian Operators ◽  
Kaluza Klein

Abstract A compact Riemannian manifold is associated with geometric data given by the eigenvalues of various Laplacian operators on the manifold and the triple overlap integrals of the corresponding eigenmodes. This geometric data must satisfy certain consistency conditions that follow from associativity and the completeness of eigenmodes. We show that it is possible to obtain nontrivial bounds on the geometric data of closed Einstein manifolds by using semidefinite programming to study these consistency conditions, in analogy to the conformal bootstrap bounds on conformal field theories. These bootstrap bounds translate to constraints on the tree-level masses and cubic couplings of Kaluza-Klein modes in theories with compact extra dimensions. We show that in some cases the bounds are saturated by known manifolds.

scholarly journals Searching for elusive dark sectors with terrestrial and celestial observations

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Roberto Contino ◽  
Kevin Max ◽  
Rashmish K. Mishra
Keyword(s):  
Field Theory ◽  
Broad Class ◽  
High Energy ◽  
Effective Field ◽  
Dark Sector ◽  
Minimum Requirement ◽  
Conformal Field ◽  
Starting Point ◽  
The Standard Model ◽  
Visible Sector

Abstract We consider the possible existence of a SM-neutral and light dark sector coupled to the visible sector through irrelevant portal interactions. Scenarios of this kind are motivated by dark matter and arise in various extensions of the Standard Model. We characterize the dark dynamics in terms of one ultraviolet scale Λuv, at which the exchange of heavy mediator fields generates the portal operators, and by one infrared scale ΛIR, setting the mass gap. At energies ΛIR « E « Λuv the dark sector behaves like a conformal field theory and its phenomenology can be studied model independently. We derive the constraints set on this scenario by high- and low-energy laboratory experiments and by astrophysical observations. Our results are conservative and serve as a minimum requirement that must be fulfilled by the broad class of models satisfying our assumptions, of which we give several examples. The experimental constraints are derived in a manner consistent with the validity of the effective field theory used to define the portal interactions. We find that high-energy colliders give the strongest bounds and exclude UV scales up to a few TeV, but only in specific ranges of the IR scale. The picture emerging from current searches can be taken as a starting point to design a future experimental strategy with broader sensitivity.

scholarly journals The DWQ-EMR Embedded Tool to Enhance the Family Physician-Caregiver Connection: A Pilot Case Study

Geriatrics ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 29
Author(s):  
Kristina Marie Kokorelias ◽  
Einat Danieli ◽  
Sheila Dunn ◽  
Sid Feldman ◽  
David Patrick Ryan ◽  
...  
Keyword(s):  
Family Caregivers ◽  
Best Practice ◽  
Data Gathering ◽  
Family Physicians ◽  
Efficient Manner ◽  
Efficient Access ◽  
Increased Risk ◽  
Starting Point ◽  
To Receive

The number of family caregivers to individuals with dementia is increasing. Family physicians are often the first point of access to the health care system for individuals with dementia and their caregivers. Caregivers are at an increased risk of developing negative physical, cognitive and affective health problems themselves. Caregivers also describe having unmet needs to help them sustain care in the community. Family physicians are in a unique position to help support caregivers and individuals with dementia, but often struggle with keeping up with best practice dementia service knowledge. The Dementia Wellness Questionnaire was designed to serve as a starting point for discussions between caregivers and family physicians by empowering caregivers to communicate their needs and concerns and to enhance family physicians’ access to specific dementia support information. The DWQ aims to alert physicians of caregiver and patient needs. This pilot study aimed to explore the experiences of physicians and caregivers of people using the Questionnaire in two family medicine clinics in Ontario, Canada. Interviews with physicians and caregivers collected data on their experiences using the DWQ following a 10-month data gathering period. Data was analyzed using content analysis. Results indicated that family physicians may have an improved efficacy in managing dementia by having dementia care case specific guidelines integrated within electronic medical records. By having time-efficient access to tailored supports, family physicians can better address the needs of the caregiver–patient dyad and help support family caregivers in their caregiving role. Caregivers expressed that the Questionnaire helped them remember concerns to bring up with physicians, in order to receive help in a more efficient manner.

Deepfaking Keanu: YouTube deepfakes, platform visual effects, and the complexity of reception

2021 ◽  
pp. 135485652110304
Author(s):  
Lisa Bode
Keyword(s):  
Film Studies ◽  
Media Theory ◽  
Digital Rhetoric ◽  
Visual Effects ◽  
After Effects ◽  
Starting Point ◽  
Media Creation ◽  
Media Practices

On July 14, 2019, a 3-minute 36-second video titled “Keanu Reeves Stops A ROBBERY!” was released on YouTube visual effects (VFX) channel, Corridor. The video’s click-bait title ensured it was quickly shared by users across platforms such as Facebook, Twitter, and Reddit. Comments on the video suggest that the vast majority of viewers categorised it as fiction. What seemed less universally recognised, though, was that the performer in the clip was not Keanu Reeves himself. It was voice actor and stuntman Reuben Langdon, and his face was digitally replaced with that of Reeves, through the use of an AI generated deepfake, an open access application, Faceswap, and compositing in Adobe After Effects. This article uses Corridor’s deepfake Keanu video (hereafter shorted to CDFK) as a case study which allows the fleshing out of an, as yet, under-researched area of deepfakes: the role of framing contexts in shaping how viewers evaluate, categorise, make sense of and discuss these images. This research draws on visual effects scholarship, celebrity studies, cognitive film studies, social media theory, digital rhetoric, and discourse analysis. It is intended to serve as a starting point of a larger study that will eventually map types of online manipulated media creation on a continuum from the professional to the vernacular, across different platforms, and attending to their aesthetic, ethical, cultural and reception dimensions. The focus on context (platform, creator channel, and comments) also reveals the emergence of an industrial and aesthetic category of visual effects, which I call here “platform VFX,” a key term that provides us with more nuanced frames for illuminating and analysing a range of manipulated media practices as VFX software becomes ever more accessible and lends itself to more vernacular uses, such as we see with various face swap apps

scholarly journals Implications of Lesson Study for Tertiary-Level EFL Teachers’ Professional Development: A Case Study From Turkey

SAGE Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 215824402110237
Author(s):  
İlknur Bayram ◽  
Fatma Bıkmaz
Keyword(s):  
Professional Development ◽  
Lesson Study ◽  
English Language ◽  
Research Question ◽  
Teaching Style ◽  
Language Teachers ◽  
Student Thinking ◽  
Pedagogical Content ◽  
Starting Point

This qualitative case study carried out at a Turkish university with four English language teachers aims to explore what teachers experience in the planning, implementation, analysis, and reporting phases of the lessons study process and what the implications of lesson study for teacher professional development can be. Data in this four-month study were gathered through observations, interviews, whole group discussions, and reflective reports. Findings revealed that lesson study had potential challenges and benefits for the professional development of teachers. The model poses challenges in finding a topic and research question, determining the lesson design and teaching style, making student thinking observable and analyzing qualitative data. On the other hand, it benefited teachers in terms of increasing their pedagogical content knowledge, reflectivity, research skills, collaboration, and collegiality. This study suggests that lesson study might be a good starting point for institutions wishing to adopt a more teacher-led, inquiry-driven and collaborative perspective for professional development.

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