The time arrow in a Planck gas

1997 ◽  
Vol 10 (3) ◽  
pp. 295-299 ◽  
Author(s):  
Miroslaw Kozlowski ◽  
Janina Marciak-Kozlowska
Keyword(s):  
Time Arrow ◽  
Planck Gas

A solution of the time paradox of physics

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Grit Kalies
Keyword(s):  
Laws Of Nature ◽  
Theoretical Physics ◽  
Quantum Level ◽  
Energy Equivalence ◽  
Time Arrow ◽  
Laws Of Thermodynamics ◽  
Time Concepts ◽  
Modern Physics ◽  
The One ◽  
Matter Energy

AbstractQuantum mechanics for describing the behavior of microscopic entities and thermodynamics for describing macroscopic systems exhibit separate time concepts. Whereas many theories of modern physics interpret processes as reversible, in thermodynamics, an expression for irreversibility and the so-called time arrow has been developed: the increase of entropy. The divergence between complete reversibility on the one hand and irreversibility on the other is called the paradox of time. Since more than hundred years many efforts have been devoted to unify the time concepts. So far, the efforts were not successful. In this paper a solution is proposed on the basis of matter-energy equivalence with an energetic distinction between matter and mass. By refraining from interpretations predominant in modern theoretical physics, the first and second laws of thermodynamics can be extended to fundamental laws of nature, which are also valid at quantum level.

INTEGRABILITY, ENTROPY AND QUANTUM COMPUTATION

1999 ◽  
Vol 10 (07) ◽  
pp. 1205-1228 ◽  
Author(s):  
E. V. KRISHNAMURTHY
Keyword(s):  
Quantum Computation ◽  
Quantum Chaos ◽  
Quantum Control ◽  
Dynamical Evolution ◽  
Open Problems ◽  
Quantum Integrability ◽  
Feynman Path Integrals ◽  
Exact Integrability ◽  
Time Arrow ◽  
Computational Systems

The important requirements are stated for the success of quantum computation. These requirements involve coherent preserving Hamiltonians as well as exact integrability of the corresponding Feynman path integrals. Also we explain the role of metric entropy in dynamical evolutionary system and outline some of the open problems in the design of quantum computational systems. Finally, we observe that unless we understand quantum nondemolition measurements, quantum integrability, quantum chaos and the direction of time arrow, the quantum control and computational paradigms will remain elusive and the design of systems based on quantum dynamical evolution may not be feasible.

scholarly journals Evolution Subject to an Energy Driven Fundamental Time Arrow

2018 ◽  
Vol 08 (03) ◽  
pp. 140-174
Author(s):  
Helmut Tributsch
Keyword(s):  
Time Arrow

scholarly journals Time arrow in published clinical studies/trials indexed in MEDLINE: a systematic analysis of Retrospective vs Prospective study design, from 1960 to 2017.

2018 ◽  
Author(s):  
Michele M Ciulla ◽  
Patrizia Vivona
Keyword(s):  
Prospective Study ◽  
Study Design ◽  
Low Income ◽  
Clinical Studies ◽  
Human Subjects ◽  
Systematic Analysis ◽  
Time Line ◽  
Time Arrow ◽  
Prospective Study Design ◽  
Single Time Point

Clinical studies/trials are experiments or observations on human subjects considered by the scientific community the most appropriate instrument to answer specific research questions on interventions on health outcomes. The time-line of the observations might be focused on a single time point or to follow time, backward or forward, in the so called, respectively, retrospective and prospective study design. Since the retrospective approach has been criticized for the possible sources of errors due to bias and confounding, we aimed this study to assess if there is a prevalence of retrospective vs prospective design in the clinical studies/trials by querying MEDLINE. Our results on a sample of 1,438,872 studies/trials, (yrs 1960-2017), support a prevalence of retrospective, respectively 55% vs 45%. To explain this result, arandom sub-sample of studies where the country of origin was reported (n=1576) was categorized in high and low-income based onthe nominal Gross Domestic Product (GDP) and matched with the topic of the research. As expected, the absolute majority of studies/trials are carried on by high-income countries, respectively 86% vs 14%; even if a slight prevalence of retrospective was recorded in both income groups, nonetheless the most part of prospective studies are carried out by high-GDP countries, 85% vs 15%. Finally the differences in the design of the study are understandable when considering the topic of the research.

Sign in / Sign up

Export Citation Format

Share Document