arXiv subjects

Decio Krause

Publications and source records attributed to Decio Krause.

13 recordsLinked to original sources

arXiv2018

Quantum mechanics, ontology, and non-reflexive logics

This is a general philosophical paper where I overview some ideas concerning the non-reflexive foundations of quantum mechanics (NRFQM). By NRFQM I mean formalism and an interpretation of QM that considers an involved ontology of non-individuals as explained in the text. Thus, I do not endorse a purely instrumentalist view of QM, but believe that it speaks of something, and then I try to show that one of the plausible views of this `something' is as entities devoid of identity conditions. Warning note: This is a revised version of a paper with the same name that was written by invitation to be published in a book titled \textit{The Mammoth Book on Quantum Mechanics Interpretations}, edited by Open Academic Press, Berlin, and having as editor a certain Ulf Edvinsson, who has invited me. The book was announced in the page of OAP and should appear by 2016. This never happened. Later I discovered that OAP is in a list of predatory editorial houses and that "Ulf Edvinsson" is (apparently) a fake name. Furthermore, I couldn't contact anyone responding by OAP to retire my name from the announcement of the book and for impeding them to publish the paper. I strongly apologize for such a fault, which is completely mine. Since the subject presented here has been among my preoccupations ever since I met Franscicso Antonio Doria for the first time (in 1987), it is a pleasure to dedicate the stuff to him. And of course I thank the editors for accepting this version of the paper for this book.

math.LO↗

arXiv2018

Does Newtonian space provide identity to quantum systems?

Physics is not just mathematics. This seems trivial, but poses difficult and interesting questions. In this paper we analyse a particular discrepancy between non-relativistic quantum mechanics (QM) and `classical' (Newtonian) space and time (NST). We also suggest, but not discuss, the case of the relativistic QM. In this work, we are more concerned with the notion of space and its mathematical representation. The mathematics entails that any two spatially separated objects are necessarily \ita{different}, which implies that they are \ita{discernible} (in classical logic, identity is defined by means of indiscernibility) --- we say that the space is $T_2$, or "Hausdorff". But when enters QM, sometimes the systems need to be taken as \ita{completely indistinguishable}, so that there is no way to tell which system is which, and this holds even in the case of fermions. But in the NST setting, it seems that we can always give an \ita{identity} to them by means of their individuation, which seems to be contra the physical situation, where individuation (isolation) does not entail identity (as we argue in this paper). Here we discuss this topic by considering a case study (that of two potentially infinite wells) and conclude that, taking into account the quantum case, that is, when physics enter the discussion, even NST cannot be used to say that the systems do have identity. This case study seems to be relevant for a more detailed discussion on the interplay between physical theories (such as quantum theory) and their underlying mathematics (and logic), in a simple way apparently never realized before.

quant-ph↗

arXiv2017

Quasi-Eheresmann-Dedecker Universes

We introduce the notion of quasi-Ehresmann-Dedecker universes in quasi-set theory in order to get a framework to develop a categorical version of quasi-set theory, so characterizing the category Qset in a similar way as the category Set is obtained from (say) ZFC plus universes. The Ehresmann-Dedecker universes generalize the usual Sonner-Grothendieck universes and are more adequate for dealing with Urelemente, which is the case of quasi-set theory. This paper is just a sketch where the main ideas are presented.

math.LO↗

arXiv2017

Contextuality and Indistinguishability

It is well known that in quantum mechanics we cannot always define consistently properties that are context independent. Many approaches exist to describe contextual properties, such as Contextuality by Default (CbD), sheaf theory, topos theory, and non-standard or signed probabilities. In this paper we propose a treatment of contextual properties that is specific to quantum mechanics, as it relies on the relationship between contextuality and indistinguishability. In particular, we propose that if we assume the ontological thesis that quantum particles or properties can be indistinguishable yet different, no contradiction arising from a Kochen-Specker-type argument appears: when we repeat an experiment, we are in reality performing an experiment measuring a property that is indistinguishable from the first, but not the same. We will discuss how the consequences of this move may help us understand quantum contextuality.

quant-ph↗

arXiv2015

Presenting Nonreflexive Quantum Mechanics: Formalism and Metaphysics

Nonreflexive quantum mechanics is a formulation of quantum theory based on a non-classical logic termed \ita{nonreflexive logic} (a.k.a. `non-reflexive'). In these logics, the standard notion of identity, as encapsulated in classical logic and set theories, does not hold in full. The basic aim of this kind of approach to quantum mechanics is to take seriously the claim made by some authors according to whom quantum particles are \ita{non-individuals} in some sense, and also to take into account the fact that they may be absolutely indistinguishable (or indiscernible). The nonreflexive formulation of quantum theory assumes these features of the objects already at the level of the underlying logic, so that no use is required of symmetrization postulates or other mathematical devices that serve to pretend that the objects are indiscernible (when they are not: all objects that obey classical logic are \ita{individuals} in a sense). Here, we present the ideas of the development of nonreflexive quantum mechanics and discuss some philosophical (mainly metaphysical) motivations and consequences of it.

quant-ph↗

arXiv2015

A logical account of quantum superpositions

In this paper we consider the phenomenon of superpositions in quantum mechanics and suggest a way to deal with the idea in a logical setting from a syntactical point of view, that is, as subsumed in the language of the formalism, and not semantically. We restrict the discussion to the propositional level only. Then, after presenting the motivations and a possible world semantics, the formalism is outlined and we also consider within this schema the claim that superpositions may involve contradictions, as in the case of the Schrödinger's cat, which (it is usually said) is both alive and dead. We argue that this claim is a misreading of the quantum case. Finally, we sketch a new form of quantum logic that involves three kinds of negations and present the relationships among them. The paper is a first approach to the subject, introducing some main guidelines to be developed by a `syntactical' logical approach to quantum superpositions.

quant-ph↗

arXiv2013

Quantum Logical Structures For Identical Particles

In this work we discuss logical structures related to indistinguishable particles. Most of the framework used to develop these structures was presented in [17, 28] and in [20, 14, 15, 16]. We use these structures and constructions to discuss possible ontologies for identical parti-cles. In other words, we use these structures in order to characterize the logical structure of quantum systems for the case of indistinguishable particles, and draw possible philosoph-ical implications. We also review some proposals available in the literature which may be considered within the framework of the quantum logical tradition regarding the problem of indistinguishability. Besides these discussions and constructions, we advance novel technical results, namely, a lattice theoretical structure for identical particles for the finite dimensional case. This kind of approach was not present in the scarcely literature of quantum logic and indistinguishable particles.

quant-ph↗

arXiv2009

Algebraic aspects of quantum indiscernibility

Quasi-set theory was proposed as a mathematical context to investigate collections of indistinguishable objects. After presenting an outline of this theory, we define an algebra that has most of the standard properties of an orthocomplete orthomodular lattice, which is the lattice of the closed subspaces of a Hilbert space. We call the mathematical structure so obtained $\mathfrak{I}$-lattice. After discussing, in a preliminary form, some aspects of such a structure, we indicate the next problem of axiomatizing the corresponding logic, that is, a logic which has $\mathfrak{I}$-lattices as its algebraic models. We suggest that the intuitions that the `logic of quantum mechanics' would be not classical logic (with its Boolean algebra), is consonant with the idea of considering indistinguishability right from the start, that is, as a primitive concept. In other words, indiscernibility seems to lead `directly' to $\mathfrak{I}$-lattices. In the first sections, we present the main motivations and a `classical' situation which mirrors that one we focus on the last part of the paper. This paper is our first study of the algebraic structure of indiscernibility within quasi-set theory.

quant-ph↗

arXiv2008

Logical aspects of quantum (non-)individuality

In this paper I consider some logical and mathematical aspects of the discussion of the identity and individuality of quantum entities. I shall point out that for some aspects of the discussion, the logical basis cannot be put aside; on the contrary, it leads us to unavoidable conclusions which may have consequences in how we articulate certain concepts related to quantum theory. Behind the discussion, there is a general argument which suggests the possibility of a metaphysics of non-individuals, based on a reasonable interpretation of quantum basic entities. I close the paper with a suggestion that consists in emphasizing that quanta should be referred to by the cardinalities of the collections to which they belong, for which an adequate mathematical framework seems to be possible.

quant-ph↗

arXiv2001

A critical study on the concept of identity in Zermelo-Fraenkel-like axioms

According to Cantor, a set is a collection into a whole of defined and separate (we shall say distinct) objects. So, a natural question is ``How to treat as `sets' collections of indistinguishable objects?". This is the aim of quasi-set theory, and this problem was posed as the first of present day mathematics, in the list resulting from the Congress on the Hilbert Problems in 1974. Despite this pure mathematical motivation, quasi-sets have also a strong commitment to the way quantum physics copes with elementary particles. In this paper, we discuss the axiomatics of quasi-set theory and sketch some of its applications in physics. We also show that quasi-set theory allows us a better and deeper understanding of the role of the concept of equality in mathematics.

math.LO↗

arXiv1998

Opaque predicates, veiled sets and their logic

Motivated by considerations in the foundations of quantum mechanics and inspired by the literature on vague predicates, we introduce the concept of an opaque predicate. While in the case of vague predicates there is a kind of indeterminacy with respect to the predicate, in the sense that the vagueness concerns whether a well-determined object satisfies it or not, in the case of opaque predicates the indeterminacy is with regard to the objects which should satisfy them. In other words, their extensions are not well-defined, despite the fact that the conditions for an object to satisfy the predicates are well-known. We suggest that such opaque predicates (and more generally, what we call opaque relations) can be characterized by a logic which encompasses a semantics founded in quasi-set theory, and call their extensions veiled sets.

quant-ph↗

arXiv1998

Quasi-set theory for bosons and fermions: quantum distributions

Quasi-set theory provides a mathematical background for dealing with collections of indistinguishable elementary particles. In this paper, we show how to obtain the quantum statistics into the scope of quasi-set theory and discuss the Helium atom, which represents the simplest example where indistinguishability plays an important role. A brief discussion about indistinguishability and interference is also presented as well as other related lines of work. One of the advantages of our approach is that one of the most basic principles of quantum theory, namely, the Indistinguishability Postulate, does not need to be assumed even implicetely in the axiomatic basis of quantum mechanics.

quant-ph↗

arXiv1996

Indistinguishable particles and hidden variables

An axiomatics for indistinguishability of elementary particles in terms of hidden variables is presented in a manner which depart from the standard approaches usually given to hidden variables. Quantum distribution functions are also discussed and some related lines of work are suggested.

quant-ph↗