Probability in Quantum Mechanics and in Utility Theory

Miwaka Yamashita

The ideas from quantum mechanics (QM) have been used as one of problem-solving methods in the field of economics, especially in game theory and decision theory, starting about “coin flip” and “prisoner’s dilemma” and now days “decision paradoxes”. In this paper, the concept of QM is applied to prudence and temperance. Classically, risk aversion, prudence, and temperance are characterized by the risk attitude toward losses and its volatility (variance), skewness, and kurtosis as well as by utility theory, where derivatives of the utility are related to risk aversion, prudence, and temperance. Here those are treated as decision paradoxes and in the QM model, probabilities of alternatives are tentatively set as unknown and a person’s subjective probabilities toward the alternatives are set as parameterized. Investigating the utility difference before averaging can show the difference among risk aversion, prudence, and temperance. In that sense, a new QM interpretation of risk aversion, prudence, and temperance as opposed to the classical interpretation was founded in the first time.

Carl Friedrich von Weizsäcker

Krzysztof Sienicki

This work introduces Algorithmic Idealism a framework that reinterprets quantum mechanics as a computational process governed by algorithmic probability informational simplicity and utility optimization Reality is modeled as an agentenvironment feedback loop where agents maximize utility by predicting selfstate transitions Core quantum phenomena such as measurement entanglement and probabilities are explained through informational constructs The paper presents a set of quantum mechanics postulates inspired by this framework and explains their mathematical meaning in detail These postulates include measurement as Bayesian updating entanglement as joint utility optimization and quantum probabilities as utilityweighted predictions Physical laws are shown to emerge as informational regularities from algorithmic constraints By defining identity through decisionmaking consistency and treating simulated and base realities as indistinguishable the framework also resolves philosophical questions about identity and reality This approach unifies quantum mechanics with computational theory offering a novel perspective on foundational physics and its connection to information and computation

Diederik Aerts

James B. Hartle

We investigate the quantum theory of closed systems based on the linear positivity decoherence condition of Goldstein and Page. The objective of any quantum theory of a closed system, most generally the universe, is the prediction of probabilities for the individual members of sets of alternative coarse-grained histories of the system. Quantum interference between members of a set of alternative histories is an obstacle to assigning probabilities that are consistent with the rules of probability theory. A quantum theory of closed systems therefore requires two elements: (1) a condition specifying which sets of histories may be assigned probabilities and (2) a rule for those probabilities. The linear positivity condition of Goldstein and Page is the weakest of the general conditions proposed so far. Its general properties relating to exact probability sum rules, time neutrality, and conservation laws are explored. Its inconsistency with the usual notion of independent subsystems in quantum mechanics is reviewed. Its relation to the stronger condition of medium decoherence necessary for classicality is discussed. The linear positivity of histories in a number of simple model systems is investigated with the aim of exhibiting linearly positive sets of histories that are not decoherent. The utility of extending the notion of probability to include values outside the range of 0--1 is described. Alternatives with such virtual probabilities cannot be measured or recorded, but can be used in the intermediate steps of calculations of real probabilities. Extended probabilities give a simple and general way of formulating quantum theory. The various decoherence conditions are compared in terms of their utility for characterizing classicality and the role they might play in further generalizations of quantum mechanics.

Arthur I. Fine