The Nature of Time Essay Contest (2008)
Measurement processes and cosmological emergence by Marni Dee Sheppeard
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As a geometrical entity, directed time traditionally follows a one dimensional path of pointlike elements, obeying the classical logic of set theory. Modern mathematics allows more general forms of logic, but time is often still considered a classical variable, which interpolates the geometry of initial and final states of a physical system. How can cosmological time be viewed as an emergent concept in geometrical logic? Using quantum logic as a clue, we investigate local time steps in algebras of finite collections of n measurement outcomes. A local concept of observer time is implicit in the measurement question, but cosmic time becomes a Hegelian measure of complexity of the observer.Author Bio
Marni D. Sheppeard is a physicist from New Zealand, who is currently employed as a cafe worker at Mt John Observatory in Tekapo. After completing her BSc(Hons) at UNSW in 1989, she spent several years working in experimental physics in Australia, and in a large variety of non academic jobs, before moving to Wanaka to be close to the mountains. Her 2007 PhD, from the University of Canterbury, discusses the relation of quantum logic to causality in a categorical approach to quantum gravity.Download Essay PDF File
i commend your revivinh your personal Physics, after a gap from professional work. It is a pity that science as a profession is increasingly becoming unprofitable for survival in this tough world of ours. The sitaution in our country is no different it seems from other places in the world. i am retired Professor of Physics with 15 years elapsed since active service at the University. i somehow maintain a semblance of activity in my profession ( experimental nuclear physicist) but all around me , i see young scientists looking for jobs outside science and technology. They are becoming administrators or financial experts but not doing justice to their professional education. It si TIME, we all do something to correct this imbalance between education cum experience versus the job on ends doing. I am not talking of you in person ,as you may well be enjoying your hilltop observatory job. May be you may like going through my speculative essay on 'Mysteries of the Universe...' as a pastime to feel more cheerful.Time has its many interesting manifestations than its meaning in dictionary or what one calls the physical TIME.
Thank you for your thoughts, Narendra, but this situation is not new. I have spent my whole adult life just barely surviving, in an effort to do a little science. But only now do I feel that things might really change for the better.
After going through your essay, it is clear that you have formulated the problem from the cosmological angle. The restriction of earth bound measurements for cosmological objects can well restrain us from such considerations as linearity of both space and time well beyond the limits of the observer. It is feasable to contemplate variation in the values of both h and c. Observations are available that indicate that both c and fine-structure constant alpha has changed for the earth -bound observer. There is definitely a big change in the universe at birth that was homogeneous with low entropy to what it is now with great heterogeneity and high entropy. On may well wonder even about the nature of the early atomic structure and the present day structure seen on the earth. There appears a dichotomy of sorts wheather the laws of Physics or strengths of fields have changed over the 14 billion years of the universe!In my essay i have made such speculations. Observations and data analysis in cosmology face several unknowable uncertaities! All the best wishes for continuing your new zest for Phyiscs, make it as fresh as you can !
I do not see how one can discuss the nature of time without some cosmological considerations, but in reality I have approached the cosmology from the point of view of mathematical particle physics, although I only refer to it very indirectly here. In the Riofrio cosmology, alpha is constant, although both h and c vary. I cannot stress enough that from this point of view, the idea of a fixed 14 billion year history for ALL observers makes no sense.
i understand Particle hysics but some how i don't feel like saying that anything physical necessarily have to be mathematical. Maths is a tool in Physics to work out the understanding os the processes after working precepts / concepts to conform to known facts/observations. Whenever, Maths gives a physically unrealistic term , the same is simple discarded. It happens all the time to the solutions of equations worked out mathematically.
i don't quite follow that alpha is a constant while h and c may vary. Why not we talk of the electronic charge too? Infact, two experiments have been performed to measure alpha form light coming from distant quasar 12 billion years away. A distinct change in value has been measures beyond the errors. Similarly, 'c' has been seen to have slightly decreased for such distant objects. The 'h' value measurements are all indirect!
I have seen some reports where it has been questioned that the terrestrial time may well be different from the cosmic time in the inter-steller regions. That certainly will have serious implications for cosmological studies if true. The problem with measurements are that what we knew about the moon has changed after actual sample came for investigation, chnaging mineral composition outside the errors of measurement. Unless, cosmic data becomes plentiful, our cosmic conjectures may get drastically affected with times!i hope you don't mind these comments ,as i am just an ordinary experimental nuclear physicist with limited knowledge in my so-called area of professional physics.
Hi Marni, Seems the idea of changing constants is more fashionable than the constants themselves. Anyway, about alpha, "New optical clock promises increased accuracy" - physicsworld.com
"...the improved accuracy of the optical clock has led the researchers at NIST to look at whether the fine-structure constant, which governs how light and electrons interact, has actually been changing over time. By measuring the ratio of clock frequencies for aluminium and mercury the researchers at NIST have concluded that the fine structure constant is not changing to within 1.6 x 10-17 per year. Indeed, they believe they have met the required precision to say that it is not changing at all. “This measurement of the ratio of aluminium and mercury clock frequencies is the most accurate known physical constant,” says Rosenband."
And I thought you might be interested in this post from my essay page:
Speaking of alpha and powers of alpha,
"...the electron and its coupling constant alpha generate not only the photon, but also the spectrum of leptons and hadrons. Thus the domain of the fine structure constant alpha seems phenomenologically to be larger than currently believed." p.72 "The Power of Alpha" by M. H. Mac Gregor
(2/3)Muon-electron mass ratio ~ 1/alpha ...from Mac Gregor.
Classical electron radius r(e) = alpha^3 / 4pi(Rydberg constant).
We noted alpha^3, pi, and 1.8 in our essay. 1.8 = 9/5.
((9/5 + (alpha^3 x pi^1/3))^-1 - 3/9 = 0.2222220466 ~ 2/9 radians.
From Carl Brannnen's alternative formulation of density matrices...
"The symmetry breaking between the electron and muon families is by a rotation by the mysterious angle delta."
"To get an exact proportionality, to current measurement error, one replaces 2/9 with ..., 0.22222204717(29)."
From Marni Sheppeard, "the phase angle determining the charged lepton mass matrix, which is 0.22222204717 to within experimental precision: notably close to 2/9.... Since phases usually involve factors of pi...."
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