104 research outputs found
F-extremization determines certain large-N CFTs
No full textWe show that the conformal data of a range of large-N CFTs, the melonic CFTs, are specified by constrained extremization of the universal part of the sphere free energy F = − log ZSd , called F˜. This family includes the generalized SYK models, the vector models (O(N), Gross-Neveu, etc.), and the tensor field theories. The known F and a-maximization procedures in SCFTs are therefore extended to these non-supersymmetric CFTs in continuous d. We establish our result using the two-particle irreducible (2PI) effective action, and, equivalently, by Feynman diagram resummation. F˜ interpolates in continuous dimension between the known C-functions, so we interpret this result as an extremization of the number of IR degrees of freedom, in the spirit of the generalized c, F, a-theorems. The outcome is a complete classification of the melonic CFTs: they are the conformal mean field theories which extremize the universal part of the sphere free energy, subject to an IR marginality condition on the interaction Lagrangian
Melonic limits of the quartic Yukawa model and general features of melonic CFTs
No full textWe study a set of large-N tensor field theories with a rich structure of fixed points, encompassing both the melonic and prismatic CFTs observed previously in the conformal limits of other tensor theories and in the generalised Sachdev-Ye-Kitaev (SYK) model. The tensor fields interact via an O(N) 3 -invariant generalisation of the quartic Yukawa model, ϕ 2ψψ¯ +ϕ 6 . To understand the structure of IR/UV fixed points, we perform a partial four-loop perturbative analysis in D = 3 − ϵ. We identify the flows between the melonic and prismatic fixed points in the bosonic and fermionic sectors, finding an apparent line of fixed points in both. We reproduce these fixed points non-perturbatively using the Schwinger-Dyson equations, and in addition identify the supersymmetric fixed points in general dimension. Selecting a particular fermionic fixed point, we study its conformal spectrum non-perturbatively, comparing it to the sextic prismatic model. In particular, we establish the dimensional windows in which this theory remains stable. We comment on the structure of large-N melonic CFTs across various dimensions, noting a number of features which we expect to be common to any such theory
Melonic limits of the quartic Yukawa model and general features of melonic CFTs
No full textWe study a set of large- tensor field theories with a rich structure of fixed points, encompassing both the melonic and prismatic CFTs observed previously in the conformal limits of other tensor theories and in the generalised Sachdev-Ye-Kitaev (SYK) model. The tensor fields interact via an -invariant generalisation of the quartic Yukawa model, . To understand the structure of IR/UV fixed points, we perform a partial four-loop perturbative analysis in . We identify the flows between the melonic and prismatic fixed points in the bosonic and fermionic sectors, finding an apparent line of fixed points in both. We reproduce these fixed points non-perturbatively using the Schwinger-Dyson equations, and in addition identify the supersymmetric fixed points in general dimension. Selecting a particular fermionic fixed point, we study its conformal spectrum non-perturbatively, comparing it to the sextic prismatic model. In particular, we establish the dimensional windows in which this theory remains stable. We comment on the structure of large- melonic CFTs across various dimensions, noting a number of features which we expect to be common to any such theory.48 pages + appendices, 16 figure
Was Henri de Man an early Post-Keynesian Neo-Marxist?
No full textHenri de Man is the author of the dissenting “Au-delà du Marxisme” (1926) and of the Belgian
Plan du Travail (Labor Plan) of 1933. Later he became a Belgian social-democratic leader. He
published between 1931 and 1935 18 economic articles in the Bulletin d’Information et de
Documentation of the National Bank of Belgium. It is shown that the articles, partly inspired by
Keynes’s writings up to 1931, are rather reflecting early Keynesian economic ideas relating to
government intervention and public works, and do not contain any reference to the multiplier
mechanism. A number of arguments in the articles are, however, advocating a Marxist inspired
underconsumption theory. Based on further analysis of these articles, it is concluded that they
contain also other important characteristics in common with the post-Keynesian neo-Marxist
economic theories developed after the Second World War, such as the importance attached
to the external markets of capitalism and a rejection of the labor theory of value, as well as
a neglect of the Marxian law of the falling rate of profits. Their economic ideas are rooted in
Marxism and the analysis of new economic phenomena, including the early Keynesianism of John
Maynard Keynes. Therefore, they should be considered as an early version of these theories
Some Comments on the Question Whether Co-Occurrence Data Should Be Normalized
No full textIn a recent article in JASIST, L. Leydesdorff and L. Vaughan (2006) asserted that raw cocitation data should be analyzed directly, without first applying a normalization such as the Pearson correlation. In this communication, it is argued that there is nothing wrong with the widely adopted practice of normalizing cocitation data. One of the arguments put forward by Leydesdorff and Vaughan turns out to depend crucially on incorrect multidimensional scaling maps that are due to an error in the PROXSCAL program in SPSS.multidimensional scaling;PROXSCAL;Pearson correlation;author cocitation analysis;co-occurrence data;normalization
A nonlocal Schwinger model
No full textWe solve a system of massless fermions constrained to two space-time dimensions interacting via a d space-time dimensional Maxwell field. Through dimensional reduction to the defect and bosonization, the system maps to a massless scalar interacting with a nonlocal Maxwell field through a Fϕ-coupling. The d = 2 dimensional case is the usual Schwinger model where the photon gets a mass. More generally, in 2 < d < 4 dimensions, the degrees of freedom map to a scalar which undergoes a renormalization group flow; in the ultraviolet, the scalar is free, while in the infrared it has scaling dimension (4 – d)/2. The infrared is similar to the Wilson-Fisher fixed point, and the physically relevant case d = 4 becomes infrared trivial in the limit of infinite ultraviolet cut-off, consistent with earlier work on the triviality of conformal surface defects in Maxwell theory
Gioco, guerra e diritto nel De ludo scacchorum in legali methodo tractatus (1583) di Tommaso Azzi
No full textThe De ludo scacchorum in legale methodo tractatus (1583) of Tommaso Azzi, is not really a treatise on the game of chess, but a work that addresses various legal issues. In De ludo the theme of war is relevant. The aim of my essay is to show how the close connection between war, game of chess and law established by Azzi is functional to the idea of just war based on the game theory. According to Azzi the war has affinities to the game: strict rules, a limited and orderly space in which to take place, a position of equality between the parties. In this treaty the author underlines similarities between war and gaming and he represents war as a regulated phenomenon, within a path of “civilisation”.Il De ludo scacchorum in legali methodo tractatus (1583) del giurista Tommaso Azzi non è realmente un trattato sul gioco degli scacchi, ma un’opera che affronta varie questioni giuridiche. Tra i temi ricorrenti del De ludo troviamo il tema della guerra. La tesi di questo saggio è mostrare come la stretta connessione tra guerra, gioco degli scacchi e diritto stabilita da Azzi sia funzionale all’affermazione di una idea di guerra giusta ricalcata sul gioco. Tale guerra deve quindi possedere le caratteristiche proprie del gioco: regole severe, uno spazio limitato e ordinato in cui svolgersi, una posizione di uguaglianza tra le parti. Il trattato si inserisce così all’interno di una tradizione che, sottolineando le similitudini tra guerra e gioco, rappresenta la guerra come un fenomeno regolato, all’interno di un percorso di “civilizzazione”
Some Comments on the Question Whether Co-occurrence Data Should Be Normalized
No full textIn a recent paper in the Journal of the American Society for Information Science and Technology, Leydesdorff and Vaughan assert that raw cocitation data should be analyzed directly, without first applying a normalization like the Pearson correlation. In this report, it is argued that there is nothing wrong with the widely adopted practice of normalizing cocitation data. One of the arguments put forward by Leydesdorff and Vaughan turns out to depend crucially on incorrect multidimensional scaling maps that are due to an error in the PROXSCAL program in SPSS.Multidimensional scaling;Author cocitation analysis;Co-occurrence data;Normalization;PROXSCAL;Pearson correlation
José Eduardo Agualusa et sa Robinsonne Ludo
No full textFrom a cross-reading with Daniel Defoe’s Robinson Crusoe, we consider José Eduardo Agualusa’s novel, Teoria Geral do Esquecimento (2012), as a postmodern Robinsonade. Indeed, the author builds his character, Ludovica Fernandes Mano, as a castaway from Portuguese colonization in Angola, after the independence of the African country. She lived as a recluse for twenty-eight years in her apartment in Luanda, before getting out with the help of a young boy, Sabalu. From then on, a postcolonial reversal takes place, since this character, although he corresponds to the figure of Robinson’s Friday, is not in a subordinate position. The relationship that is established between Ludo and Sabalu is made up of mutual aid, care and reciprocal exchanges, a far cry from the unequivocal and ethnocentric relationship of Defoe’s novel.À partir d’une lecture croisée avec le Robinson Crusoe, de Daniel Defoe, nous envisageons le roman de José Eduardo Agualusa, Teoria Geral do Esquecimento (2012), comme une robinsonnade postmoderne. En effet, l’auteur construit son personnage, Ludovica Fernandes Mano, comme une naufragée de la colonisation portugaise en terres angolaises, au sortir de l’indépendance du pays africain. Elle vit recluse durant vingt-huit ans dans son appartement luandais, avant d’en sortir grâce à l’aide d’un jeune garçon, Sabalu. Dès lors, il s’opère un renversement postcolonial, puisque ce personnage, bien qu’il corresponde à la figure du Vendredi de Robinson, n’est pas dans une position subalterne. La relation qui s’établit entre Ludo et Sabalu est faite d’entraide, de sollicitude et d’échanges réciproques, bien loin donc de la relation univoque et ethnocentrée du roman de Defoe
Ludo-Emotional Dissonance: A Framework for Analyzing the Interplay Between Player Embodiment and Interactivity within Videogames
No full textVideogames are vehicles for player embodiment, unique interactive experiences, mechanic challenges, and exploration of other worlds and lives. However, much of the mainstream videogame industry is predicated upon principles which perpetuate certain values while excluding many players from being able to experience these unique pieces of art. These frameworks work off of principles such as “fun” and profit as the key drivers for videogame creation, as well as white supremacist values of being “apolitical”, mastery and dominance, and how the diversification of the industry is “woke” rather than dismantling hegemonic values. In this way, mainstream videogames cyclically recreate themselves for the hegemon, excluding players, diverse experiences, and complex emotional explorations.
In this work I explore some of the aspects cemented within mainstream videogame design as well as what has been less explored or is only now coming to the mainstream including emotional responses of players - expanding beyond if the game is bugged or mechanically “good” - as well as questioning the levels of interactivity players are exposed to regularly within these games. I adapt and build upon the concept of ludo-narrative dissonance to create the framework of ludo-emotional dissonance which is meant to be used to analyze games and how games can be positively or negatively received by different players for different reasons, as well as how player experience, player expectations, and designer intentions work to form a consonant or dissonant experience. Ludo-emotional dissonance works upon the interplay of embodiment, which includes the player’s own socio-cultural experiences and their role situated within the environmental context of the game, as well as interactivity, which mediates the player’s embodiment. Unlike many mainstream frameworks, I posit that more interactivity does not necessarily mean a better player experience. Instead, designer intentions should be mediated by a level of interactivity which will meet the player experience, which is also determined by the player expectations prior to gameplay, thus creating a “better” player experience and which does not rely on more interactivity.
I use the framework of ludo-emotional dissonance to explore works such as Detroit: Become Human (2018), and how its author claiming it as apolitical reveals a deeper tendency within mainstream games to view white as the default, thus alienating players, rejecting emotional nuances, and rejecting deeper readings of their works. I also look at games such as What Remains of Edith Finch (2017) and how it problematizes the concept of interactivity by using less interaction to make a more accessible and approachable game for players, thus creating a ludo-emotionally consonant experience by opening up the narrative possibility space and encouraging deductive reasoning through environmental storytelling rather than through generic interactive elements. I also create a case study for Doki Doki Literature Club! (2017), and how its elements create a ludo-emotionally dissonant experience through interference between player expectations and their actual experience, and yet one which creates strong player engagement, all while disrupting mainstream game creation conventions. DDLC does this through the use of a detailed content warning at the beginning of the game, a subversion of dating simulation genre conventions, the overpowering use of glitches which narrow the player interaction space, and the theme of hopelessness which pervades the entire work
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