Quantum reference frame transformations have been proposed to provide a means by which to translate descriptions of quantum systems relative to each other. At present, there are several differing frameworks for describing quantum reference frames, with concomitantly different transformation rules. Here, we investigate a simple example of three qubit systems with ℤ_2 symmetry in order to analyze physical and conceptual distinctions between three contemporary approaches to quantum reference frames – dubbed perspective-neutral, extra particle and operational. By constructing two three-qubit states that are indistinguishable by observables relative to one frame but are distinguishable by observables relative to another, we show that each of the three approaches provides a distinct transformation rule, which may be understood to reflect differing attitudes towards the global state and the information that can be accessed by each frame. This helps us to shed light on the operational meaning of each approach and the contexts in which they may be most naturally applied.
The purpose of the current study was to test the necessity of basic psychological needs within self-determination theory (SDT) for employee wellbeing. Utilizing necessary condition analysis across three samples (two cross-sectional and one longitudinal), we evaluate whether need satisfaction and need frustration of the basic psychological needs for autonomy, competence, and relatedness are essential for various indicators of well-being and ill-being among employees. The results, although varied across samples and outcomes, generally indicated that autonomy and competence constitute necessities for employee wellbeing. Specifically, both satisfaction and low frustration of autonomy were necessary for promoting well-being and avoiding ill-being, while low frustration of competence emerged as a consistent necessity across a broad spectrum of well-being indicators. In contrast, the need for relatedness did not consistently emerge as necessary across the studied outcomes but was identified as necessary for certain ones. Together these findings validate the necessity assumption of the basic psychological needs posited by SDT and illuminates the dual role of satisfaction and frustration for employee wellbeing.
Work motivation has been a central topic for over a century with self-determination theory (SDT) shaping its trajectory. This review aims to (1) provide a comprehensive overview of the state of work-related SDT research and (2) develop expansions of SDT to pave the way for future research. To achieve our first goal, we leveraged co-word bibliometric science mapping to analyze 1,192 articles, resulting in six clusters belonging to three overarching themes: satisfaction of the basic psychological needs, motivation quality and determinants, and motivation-relevant individual and organizational factors. Temporal analyses suggest a progressive trajectory characterized by central tenets that have expanded and integrated over time, with evidence of recent stagnation. For our second goal, a research agenda, summarized in a model of self-determination theory for work environments, integrates individual factors and four broad approaches: horizontal and vertical expansions, consideration of alternative work arrangements, and technological changes as drivers and boundary conditions.
There has been a wave of recent interest in detecting the quantum nature of gravity with table-top experiments that witness gravitationally mediated entanglement. Central to these proposals is the assumption that any mediator capable of generating entanglement must itself be nonclassical. However, previous arguments for this have modelled classical mediators as finite, discrete systems such as bits, which excludes physically relevant continuous and infinite-dimensional systems such as those of classical mechanics and field theory. In this work, we close this gap by modelling classical systems as commutative unital C*-algebras, arguably encompassing all potentially physically relevant classical systems. We show that these systems cannot mediate entanglement between two quantum systems A and B, even if A and B are themselves infinite-dimensional or described by arbitrary unital C*-algebras (as in Quantum Field Theory), composed with an arbitrary C*-tensor product. This result reinforces the conclusion that the observation of gravity-induced entanglement would require the gravitational field to possess inherently non-classical features.
Inspired by recent advances in the manipulation of superconducting circuits coupled to mechanical modes in the quantum regime, we propose a protocol for generating superpositions of orthogonally squeezed states in a quantum harmonic oscillator. The protocol relies on a quadratic coupling between the oscillator and a qubit, and is conceptually similar to methods used for preparing cat states in qubit-oscillator systems. We numerically evaluate the robustness of the state-preparation scheme in the presence of decoherence, considering environmental coupling for both the harmonic oscillator and the qubit. As a potential application, we consider a quantum error-correcting code based on conditionally squeezed states and analyze its error correction properties.
