Quantum Weak Invariants: Dynamical Evolution of Fluctuations and Correlations.

Entropy (Basel)

Department of Physics, College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China.

Published: October 2020

Weak invariants are time-dependent observables with conserved expectation values. Their fluctuations, however, do not remain constant in time. On the assumption that time evolution of the state of an open quantum system is given in terms of a completely positive map, the fluctuations monotonically grow even if the map is not unital, in contrast to the fact that monotonic increases of both the von Neumann entropy and Rényi entropy require the map to be unital. In this way, the weak invariants describe temporal asymmetry in a manner different from the entropies. A formula is presented for time evolution of the covariance matrix associated with the weak invariants in cases where the system density matrix obeys the Gorini-Kossakowski-Lindblad-Sudarshan equation.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7711532PMC
http://dx.doi.org/10.3390/e22111219DOI Listing

Publication Analysis

Top Keywords

weak invariants
16
time evolution
8
map unital
8
quantum weak
4
invariants
4
invariants dynamical
4
dynamical evolution
4
evolution fluctuations
4
fluctuations correlations
4
correlations weak
4

Similar Publications

MEFA-Net: A mask enhanced feature aggregation network for polyp segmentation.

Comput Biol Med

December 2024

Fujian Provincial Key Laboratory of Networking Computing and Intelligent Information Processing, College of Computer and Data Science, Fuzhou University, Fuzhou 350116, China; Engineering Research Center of Big Data Intelligence, Ministry of Education, Fuzhou 350116, China. Electronic address:

Accurate polyp segmentation is crucial for early diagnosis and treatment of colorectal cancer. This is a challenging task for three main reasons: (i) the problem of model overfitting and weak generalization due to the multi-center distribution of data; (ii) the problem of interclass ambiguity caused by motion blur and overexposure to endoscopic light; and (iii) the problem of intraclass inconsistency caused by the variety of morphologies and sizes of the same type of polyps. To address these challenges, we propose a new high-precision polyp segmentation framework, MEFA-Net, which consists of three modules, including the plug-and-play Mask Enhancement Module (MEG), Separable Path Attention Enhancement Module (SPAE), and Dynamic Global Attention Pool Module (DGAP).

View Article and Find Full Text PDF

Aim: To replicate and extend previous psychometric findings for the Autism Symptom Dimensions Questionnaire (ASDQ).

Method: Using a cross-sectional design in two samples, including a total of 3366 children and adolescents (aged 2-17 years; 1399 with autism spectrum disorder) and a small case series, factor structure, measurement invariance, reliability, construct validity, screening and diagnostic efficiency, and detection of reliable change were examined for the ASDQ.

Results: Strong psychometric properties were observed, including replicable factor structure, strong measurement invariance, adequate-to-excellent scale and conditional reliability, strong convergent and discriminant validity, and good screening efficiency.

View Article and Find Full Text PDF

Introduction: Immunotherapy with checkpoint inhibition (ICI) is increasingly prescribed to older patients with cancer. High age, especially in combination with frailty, has been associated to immune senescence, which is the age-related decline in immune function, thereby possibly hindering ICI effectiveness. This cross-sectional study aimed to assess whether blood cell immune senescence markers are associated with age, frailty and response to anti-PD-1 treatment in older patients with metastatic melanoma.

View Article and Find Full Text PDF

Symmetry invariants of a group specify the classes of quasiparticles, namely the classes of projective irreducible co-representations in systems having that symmetry. More symmetry invariants exist in discrete point groups than the full rotation group O(3), leading to new quasiparticles restricted to lattices that do not have any counterpart in a vacuum. We focus on the fermionic quasiparticle excitations under "spin-space group" symmetries, applicable to materials where long-range magnetic order and itinerant electrons coexist.

View Article and Find Full Text PDF

Educational and psychological tests with an ordered item structure enable efficient test administration procedures and allow for intuitive score interpretation and monitoring. The effectiveness of the measurement instrument relies to a large extent on the validated strength of its ordering structure. We define three increasingly strict types of ordering for the ordering structure of a measurement instrument with clustered items: a weak and a strong invariant cluster ordering and a clustered invariant item ordering.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!