This essay considers the prospects of modeling spacetime as a phenomenon that emerges in the low-energy limit of a quantum liquid. It evaluates three examples of spacetime analogues in condensed matter systems that have appeared in the recent physics literature, indicating the extent to which they are viable, and considers what they suggest about the nature of spacetime.

In this essay, I consider what condensed matter physics has to say about the nature of spacetime. In particular, I consider the extent to which spacetime can be modeled as a quantum liquid, with matter and force fields described by effective field theories of the low-energy excitations of the liquid. After a brief review of effective field theories in 2-dim highly-correlated condensed matter systems, I evaluate analogies in the recent physics literature between spacetime and superfluid Helium, and proposals that suggest (...) spacetime is an emergent phenomenon arising from the edge states of a 4-dim Quantum Hall liquid. KeyworCh: spacetime, effective field theory, condensed matter, quantum gravity.. (shrink)

A model \ of ZF is said to be condensable if \\prec _{\mathbb {L}_{{\mathcal {M}}}} {\mathcal {M}}\) for some “ordinal” \, where \:=,\in )^{{\mathcal {M}}}\) and \ is the set of formulae of the infinitary logic \ that appear in the well-founded part of \. The work of Barwise and Schlipf in the 1970s revealed the fact that every countable recursively saturated model of ZF is cofinally condensable \prec _{\mathbb {L}_{{\mathcal {M}}}}{\mathcal {M}}\) for an unbounded collection of \). Moreover, it (...) can be readily shown that any \-nonstandard condensable model of \ is recursively saturated. These considerations provide the context for the following result that answers a question posed to the author by Paul Kindvall Gorbow.Theorem A. Assuming a modest set-theoretic hypothesis, there is a countable model \ of ZFC that is both definably well-founded is in the well-founded part of \}\) and cofinally condensable. We also provide various equivalents of the notion of condensability, including the result below.Theorem B. The following are equivalent for a countable model \ of \: \ is condensable. \ is cofinally condensable. \ is nonstandard and \\prec _{\mathbb {L}_{{\mathcal {M}}}}{\mathcal {M}}\) for an unbounded collection of \. (shrink)

Inner speech has been shown to vary in form along several dimensions. Along condensation, condensed inner speech forms have been described, that are supposed to be deprived of acoustic, phonological and even syntactic qualities. Expanded forms, on the other extreme, display articulatory and auditory properties. Along dialogality, inner speech can be monologal, when we engage in internal soliloquy, or dialogal, when we recall past conversations or imagine future dialogues involving our own voice as well as that of others addressing (...) us. Along intentionality, it can be intentional (when we deliberately rehearse material in short-term memory) or it can arise unintentionally (during mind wandering). We introduce the ConDialInt model, a neurocognitive predictive control model of inner speech that accounts for its varieties along these three dimensions. ConDialInt spells out the condensation dimension by including inhibitory control at the conceptualization, formulation or articulatory planning stage. It accounts for dialogality, by assuming internal model adaptations and by speculating on neural processes underlying perspective switching. It explains the differences between intentional and spontaneous varieties in terms of monitoring. We present an fMRI study in which we probed varieties of inner speech along dialogality and intentionality, to examine the validity of the neuroanatomical correlates posited in ConDialInt. Condensation was also informally tackled. Our data support the hypothesis that expanded inner speech recruits speech production processes down to articulatory planning, resulting in a predicted signal, the inner voice, with auditory qualities. Along dialogality, covertly using an avatar’s voice resulted in the activation of right hemisphere homologues of the regions involved in internal own-voice soliloquy and in cerebellar deactivation, consistent with internal model adaptation. Switching from first-person to third-person perspective resulted in activations in precuneus and parietal lobules. Along intentionality, compared with intentional inner speech, mind wandering with inner speech episodes was associated with greater bilateral inferior frontal activation and decreased activation in left temporal regions. This is consistent with the reported subjective evanescence and presumably reflects condensation processes. Our results provide neuroanatomical evidence compatible with predictive control and in favor of the assumptions made in the ConDialInt model. (shrink)

Condensed detachment is usually regarded as a notation, and defined by example. In this paper it is regarded as a rule of inference, and rigorously defined with the help of the Unification Theorem of J. A. Robinson. Historically, however, the invention of condensed detachment by C. A. Meredith preceded Robinson's studies of unification. It is argued that Meredith's ideas deserve recognition in the history of unification, and the possibility that Meredith was influenced, through ukasiewicz, by ideas of Tarski going back (...) at least to 1939, and possibly to 1930 or earlier, is discussed. It is proved that a term is derivable by substitution and ordinary detachment from given axioms if and only if it is a substitution instance of a term which is derivable from these axioms by condensed detachment, and it is shown how this theorem enables the ideas of ukasiewicz and Tarski mentioned above to be formalized and extended. Finally, it is shown how condensed detachment may be subsumed within the resolution principle of J. A. Robinson, and several computer studies of particular Hilbert-type propositional calculi using programs based on condensed detachment or on resolution are briefly discussed. (shrink)

It is widely hoped that quantum gravity will shed light on the question of the origin of time in physics. The currently dominant approaches to a candidate quantum theory of gravity have naturally evolved from general relativity, on the one hand, and from particle physics, on the other hand. A third important branch of twentieth century ‘fundamental’ physics, condensed-matter physics, also offers an interesting perspective on quantum gravity, and thereby on the problem of time. The bottomline might sound disappointing: to (...) understand the origin of time, much more experimental input is needed than what is available today. Moreover it is far from obvious that we will ever find out the true origin of physical time, even if we become able to directly probe physics at the Planck scale. But we might learn some interesting lessons about time and the structure of our universe in the process. A first lesson is that there are probably several characteristic scales associated with “quantum gravity” effects, rather than the single Planck scale usually considered. These can differ by several orders of magnitude, and thereby conspire to hide certain effects expected from quantum gravity, rendering them undetectable even with Planck-scale experiments. A more tentative conclusion is that the hierarchy between general relativity, special relativity and Newtonian physics, usually taken for granted, might have to be interpreted with caution. (shrink)

The Hartree–Fock–Popov theory of interacting Bose particles is generalized to the Cooper-pair system with a screened Coulomb repulsive interaction in high-temperature superconductors. At zero temperature, it is found that the condensate density \\) of Cooper pairs is of the order \\simeq 10^{18}\) cm\, consistently with the fact that a small fraction of the total p holes participate in pairing. We find that the phonon velocity c at zero temperature is of the order \\simeq 10\) km s\. The computation shows that (...) the transition temperature \ is a dome-shaped function of the p hole concentration \, which is consistent with experiments. At finite temperature, we find that the condensate fraction \/n\) decreases continuously from \/n\) to zero as the temperature increases from zero to the transition temperature \. For higher temperatures, we find that the repulsive interaction between Cooper pairs drives more Cooper pairs into the condensate. The computation reveals that the phonon velocity c decreases continuously from c to zero as the temperature increases from zero to the transition temperature \. The Cooper-pair system undergoes a first-order phase transition from the normal state to the BEC state. (shrink)

Many abiotic and other signals are transduced in eukaryotic cells by changes in the level of free calcium via pumps, channels and stores. We suggest here that ion condensation should also be taken into account. Calcium, like other counterions, is condensed onto linear polymers at a critical value of the charge density. Such condensation resembles a phase transition and has a topological basis in that it is promoted by linear as opposed to spherical assemblies of charges. Condensed counterions (...) are delocalised and can diffuse in the so‐called near region along the polymers. It is generally admitted that cytoskeletal filaments, proteins colocalised with these filaments, protein filaments distinct from cytoskeletal filaments, and filamentous assemblies of other macromolecules, constitute an intracellular macromolecular network. Here we draw attention to the fact that this network has physicochemical characteristics that enable counterion condensation. We then propose a model in which the feedback relationships between the condensation/decondensation of calcium and the activation of calcium‐dependent kinases and phosphatases control the charge density of the filaments of the intracellular macromolecular network. We show how condensation might help mediate free levels of calcium both locally and globally. In this model, calcium condensation/decondensation on the macromolecular network creates coherent patterns of protein phosphorylation that integrate signals. This leads us to hypothesize that the process of ion condensation operates in signal transduction, that it can have an integrative role and that the macromolecular network serves as an integrative receptor. BioEssays 26:549–557, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

ABSTRACT In this article I read Freud’s theory of dream condensation alongside Blanchot and Derrida’s analysis of the literary fragment. Both these thinkers describe how an imperturbable secret provides an excess that calls out for a response. I thus analyze the structure of dream interpretation as one where the latent dream thoughts respond to a call imbedded in the condensed dream-content. Through a deconstructive reading of Freud and a quote by Nietzsche, I argue that the structure of this call (...) is the condensation of the secret, which is both a mark and occurrence of forgetting. (shrink)

We address anticipated fermion–antifermion and dimension-4 gauge-field vacuum-condensate contributions to the magnetic portion of the fermion–photon vertex function in the presence of a vacuum with nonperturbative content, such as that of QCD. We discuss how inclusion of such condensate contributions may lead to a vanishing anomalous magnetic moment, in which case vacuum condensates may account for the apparent consistency between constituent quark masses characterizing baryon magnetic moments and those characterizing baryon spectroscopy.

Corollaire à "l'homme mesure de toute chose" se place "l'homme démesure de toute chose". La démesure n'est pas dommageable en soi, ne pas prendre la mesure de cette démesure ni engager une culture préparant à digérer la démesure est par contre désastreux. Toute médiation est aussi facteur de démesure. Première des médiations humaines, le langage verbal entre dans un vertige de la démesure, à la mesure des médiations technologiques et de leur puissance inouïe. Cet essai sur la condensation se (...) place dans l'effort pour penser les fondements de la médiation symbolique et ce à partir d'une économie sensible de la représentation qui prend pour appui le langage plastique. Kim Leroy est docteur en Philosophie et lettres de l'Université libre de Bruxelles (2006). il enseigne la philosophie de l'art et la sémiologie des médias à l'académie royale des Beaux-arts de Bruxelles et à Arts2 à Mons. coopérateur à la coopérative Quatre Quarts à court-saint-Etienne, il est aussi observateur au conseil d'administration du Mundaneum à Mons et Membre de SEA (sustainable economy association). (shrink)

The complexity of aII 4 set of natural numbers is encoded into a linear order to show that the finite condensation of a recursive linear order can beII 2–II 1. A priority argument establishes the same result, and is extended to a complete classification of finite condensations iterated finitely many times.

This paper considers the issue of Bose–Einstein condensation in a weakly interacting Bose gas with a fixed total number of particles. We use an old current algebra formulation of non-relativistic many body systems due to Dashen and Sharp to show that, at sufficiently low temperatures, a gas of weakly interacting Bosons displays Off-diagonal Long Range Order in the sense introduced by Penrose and Onsager. Even though this formulation is somewhat cumbersome it may demystify many of the standard results in (...) the field for those uncomfortable with the conventional broken symmetry based approaches. All the physics presented here is well understood but as far as we know this perspective, although dating from the 60's and 70's, has not appeared in the literature. We have attempted to make the presentation as self-contained as possible in the hope that it will be accessible to the many students interested in the field. (shrink)

Phase separation underlies the formation of biomolecular condensates. We hypothesize the cellular processes that occur within condensates shape their structural features. We use the example of transcription to discuss structure–function relationships in condensates. Various types of transcriptional condensates have been reported across the evolutionary spectrum in the cell nucleus as well as in mitochondrial and bacterial nucleoids. In vitro and in vivo observations suggest that transcriptional activity of condensates influences their supramolecular structure, which in turn affects their function. Condensate organization (...) thus becomes driven by differences in miscibility among the DNA and proteins of the transcription machinery and the RNA transcripts they generate. These considerations are in line with the notion that cellular processes shape the structural properties of condensates, leading to a dynamic, mutual interplay between structure and function in the cell. (shrink)

An introduction to the area of condensed matter in a nutshell. This textbook covers the standard topics, including crystal structures, energy bands, phonons, optical properties, ferroelectricity, superconductivity, and magnetism.

This book addresses a wide range of topics relating to the properties and behavior of condensed matter under extreme conditions such as intense magnetic and electric fields, high pressures, heat and cold, and mechanical stresses. It is divided into four sections devoted to condensed matter theory, molecular chemistry, theoretical physics, and the philosophy and history of science. The main themes include electronic correlations in material systems under extreme pressure and temperature conditions, surface physics, the transport properties of low-dimensional electronic systems, (...) applications of the density functional theory in molecular systems, and graphene. The book is the outcome of a workshop held at the University of Catania, Italy, in honor of Professor Renato Pucci on the occasion of his 70th birthday. It includes selected invited contributions from collaborators and co-authors of Professor Pucci during his long and successful career, as well as from other distinguished guest authors. (shrink)

We present the bundle (Aff(3)⊗ℂ⊗Λ)(ℝ3), with a geometric Dirac equation on it, as a three-dimensional geometric interpretation of the SM fermions. Each (ℂ⊗Λ)(ℝ3) describes an electroweak doublet. The Dirac equation has a doubler-free staggered spatial discretization on the lattice space (Aff(3)⊗ℂ)(ℤ3). This space allows a simple physical interpretation as a phase space of a lattice of cells.We find the SM SU(3) c ×SU(2) L ×U(1) Y action on (Aff(3)⊗ℂ⊗Λ)(ℝ3) to be a maximal anomaly-free gauge action preserving E(3) symmetry and symplectic (...) structure, which can be constructed using two simple types of gauge-like lattice fields: Wilson gauge fields and correction terms for lattice deformations.The lattice fermion fields we propose to quantize as low energy states of a canonical quantum theory with ℤ2-degenerated vacuum state. We construct anticommuting fermion operators for the resulting ℤ2-valued (spin) field theory.A metric theory of gravity compatible with this model is presented too. (shrink)

This paper gives a simple, elegant statement of the condensed detachment rule that is independent of most general unifiers and proves that this is equivalent to the longer, more usual, formulation.

According to prevailing theory, relativistic degenerate stars with masses beyond the Chandrasekhar and Oppenheimer–Volkoff (OV) limits cannot achieve hydrostatic equilibrium through either electron or neutron degeneracy pressure and must collapse to form stellar black holes. In such end states, all matter and energy within the Schwarzschild horizon descend into a central singularity. Avoidance of this fate is a hoped-for outcome of the quantization of gravity, an as-yet incomplete undertaking. Recent studies, however, suggest the possibility that known quantum processes may intervene (...) to arrest complete collapse, thereby leading to equilibrium states of macroscopic size and finite density. I describe here one such process which entails pairing (or other even-numbered association) of neutrons (or constituent quarks in the event of nucleon disruption) to form a condensate of composite bosons in equilibrium with a core of degenerate fermions. This process is analogous to, but not identical with, the formation of hadron Cooper pairs that give rise to neutron superfluidity and proton superconductivity in neutron stars. Fermion condensation to composite bosons in a star otherwise destined to collapse to a black hole facilitates hydrostatic equilibrium in at least two ways: (1) removal of fermions results in a decrease in the Fermi level which stiffens the dependence of degeneracy pressure on fermion density, and (2) phase separation into a fermionic core surrounded by a self-gravitating condensate diminishes the weight which must be balanced by fermion degeneracy pressure. The outcome is neither a black hole nor a neutron star, but a novel end state, a “fermicon star,” with unusual physical properties. (shrink)

Recent studies indicate that mammalian chromosomes contain discretecis‐acting loci that control replication timing, mitotic condensation, and stability of entire chromosomes. Disruption of the large non‐coding RNA gene ASAR6 results in late replication, an under‐condensed appearance during mitosis, and structural instability of human chromosome 6. Similarly, disruption of the mouse Xist gene in adult somatic cells results in a late replication and instability phenotype on the X chromosome. ASAR6 shares many characteristics with Xist, including random mono‐allelic expression and asynchronous replication (...) timing. Additional “chromosome engineering” studies indicate that certain chromosome rearrangements affecting many different chromosomes display this abnormal replication and instability phenotype. These observations suggest that all mammalian chromosomes contain “inactivation/stability centers” that control proper replication, condensation, and stability of individual chromosomes. Therefore, mammalian chromosomes contain four types ofcis‐acting elements, origins, telomeres, centromeres, and “inactivation/stability centers”, all functioning to ensure proper replication, condensation, segregation, and stability of individual chromosomes. (shrink)

Inspired by “One Note Samba,” a standard jazz repertoire, we present an outline of Bose-Einstein Condensate Cosmology (BECC). Although this approach seems awkward and a bit off the wall at first glance, it is not impossible to connect altogether BEC, Scalar Field Cosmology and Feshbach Resonance with Ermakov-Pinney equation. We also discuss shortly possible link with our previous paper, where we describe Newtonian Universe with Vortex in terms of Ermakov equation.

The physics of condensed matter, in contrast to quantum physics or cosmology, is not traditionally associated with deep philosophical questions. However, as science - largely thanks to more powerful computers - becomes capable of analysing and modelling ever more complex many-body systems, basic questions of philosophical relevance arise. Questions about the emergence of structure, the nature of cooperative behaviour, the implications of the second law, the quantum-classical transition and many other issues. This book is a collection of essays by leading (...) physicists and philosophers. Each investigates one or more of these issues, making use of examples from modern condensed matter research. Physicists and philosophers alike will find surprising and stimulating ideas in these pages. (shrink)

The "groupie" tendency of bosons has recently been demonstrated in a breakthrough experiment by Carl Wieman of the University of Colorado and Eric Cornell of the National Institute for Standards and Technology and their group. They were able to cool a gas of rubidium-87 atoms to a temperature so low that thousands of atoms coalesced into the same quantum state, forming a new state of matter called a Bose-Einstein condensate (BEC). This column is about that work.

The Axiom of Strong Condensation, first introduced by Woodin in [14], is an abstract version of the Condensation Lemma ofL. In this paper, we construct a set-sized forcing to obtain Strong Condensation forH. As an application, we show that “ZFC + Axiom of Strong Condensation +”is consistent, which answers a question in [14]. As another application, we give a partial answer to a question of Jech by proving that “ZFC + there is a supercompact cardinal + (...) any ideal onω1which is definable overH is not precipitous” is consistent under sufficient large cardinal assumptions. (shrink)

Condensed matter approaches to quantum gravity suggest that spacetime emerges in the low-energy sector of a fundamental condensate. This essay investigates what could be meant by this claim. In particular, I offer an account of low-energy emergence that is appropriate to effective field theories in general, and consider the extent to which it underwrites claims about the emergence of spacetime in effective field theories of condensed matter systems of the type that are relevant to quantum gravity.

Paraspeckles are nuclear condensates, or membranelees organelles, that are built on the long noncoding RNA, NEAT1, and have been linked to many diseases. Although originally described as constitutive structures, here, in reviewing this field, we develop the hypothesis that cells increase paraspeckle abundance as part of a general stress response, to aid pro‐survival pathways. Paraspeckles increase in many scenarios: when cells transform from one state to another, become infected with viruses and bacteria, begin to degenerate, under inflammation, in aging, and (...) in cancer. Cells increase paraspeckles by increasing transcription of NEAT1 and adjusting its RNA processing. These increases in NEAT1 are driven by numerous stress‐sensing signaling pathways, including signaling to mitochondria and stress granules, revealing crosstalk between the cytoplasm and nucleoplasm in the stress response. Thus, paraspeckles are an important piece of the puzzle in cellular homeostasis, and could be considered RNA‐scaffolded nuclear equivalents of dynamic stress‐induced structures that form in the cytoplasm. We speculate that, in general, cells rely on phase‐separated paraspeckles to transiently tweak gene regulation in times of cellular flux. (shrink)

Although not generally regarded as a significant area of inquiry, the condensation of argumentative structures and the presence of `miniaturized' yet self-sufficient arguments in stand-alone, sub-discursive linguistic units, especially those below the level of a compound sentence, deserve a close look. Built skillfully into key words, catchy phrases, subtly appealing tropes, etc., these condensed arguments are often instrumental in accounting for the way some small linguistic units work magic on the audience. Taking such mini structures seriously holds two promises (...) for argumentation studies: a widened scope of investigation and a unique contribution to the understanding of how rhetorical effects are being produced at the sub-syntactic or lexical level. (shrink)

The Bose-Einstein condensation of free relativistic particles [ε=(M 2 c 4 +c 2 p 2 ) 1/2 −Mc 2 ] is studied rigorously. For massless bosons (ε=cp), the condensation transition of third (second) order occurs in2 (3) dimensions (D). The molar heat capacity follows the T 2 (T 3 ) law below the condensation temperature Tc [k B Tc=(2πħ 2 c 2 n/1.645) 1/2 [(π 2 ħ 3 c 3 n/1.202) 1/3 ], reaches4.38 (10.8) R at T=Tc, (...) and approaches the high-temperature-limit value2 (3) R with no jump (a jump equal to6.75R) in2 (3)D. For finite-mass (M) bosons, the phase transition occurs only in3D with the condensation temperature Tc always smaller than that of the corresponding nonrelativistic bosons [ε=(2M) −1 p 2 ]. If the mass M is reduced to zero, the condensation temperature Tc grows monotonically and reaches eventually that of massless relativistic bosons. This mass-dependence of Tc is therefore distinct from the case of nonrelativistic bosons, where Tc grows to infinity as M →0. A brief discussion is given for a possible connection with the normal-to-super transition of the independently moving Cooper pairs (bosons). (shrink)

In the first part of this paper we indicate how Meredith's condensed detachment may be used to give a new proof of Belnap's theorem that if every axiom x of a calculus S has the two-property that every variable which occurs in x occurs exactly twice in x, then every theorem of S is a substitution instance of a theorem of S which has the two-property. In the remainder of the paper we discuss the use of mechanical theorem-provers, based either (...) on condensed detachment or on the resolution rule of J. A. Robinson, to investigate various calculi whose axioms all have the two-property. Particular attention is given to D-groupoids, i.e. sets of formulae which are closed under condensed detachment. (shrink)