اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدPhysics in 100 Years
54
0
0.0
(
0
)
تأليف
Frank Wilczek
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Here I indulge in wide-ranging speculations on the shape of physics, and technology closely related to physics, over the next one hundred years. Themes include the many faces of unification, the re-imagining of quantum theory, and new forms of engineering on small, intermediate, and large scales.
قيم البحث
اقرأ أيضاً
In 1995, a team of physicists from the Budker Institute of Nuclear Physics in Novosibirsk was able to observe the splitting of a photon in the Coulomb field of an atomic nucleus for the first time, and reported the preliminary results of this experim
ent at two conferences. This was an extremely difficult experiment as the probability of the process is very small. It took another seven years to publish the final results. This story has been further developed recently. The ATLAS detector at the Large Hadron Collider observed in ultra-peripheral heavy ion collisions a process related to the photon splitting - light by light scattering. In addition, a team of Italian, Polish and British astrophysicists obtained the first observational evidence of the existence of vacuum birefringence in the magnetic field of an isolated neutron star - another physical phenomenon also related to the photon splitting. These new developments triggered this essay, written several years ago.
The aim of this paper is to bring a mathematical justification to the optimal way of organizing ones effort when running. It is well known from physiologists that all running exercises of duration less than 3mn are run with a strong initial accelerat
ion and a decelerating end; on the contrary, long races are run with a final sprint. This can be explained using a mathematical model describing the evolution of the velocity, the anaerobic energy, and the propulsive force: a system of ordinary differential equations, based on Newtons second law and energy conservation, is coupled to the condition of optimizing the time to run a fixed distance. We show that the monotony of the velocity curve vs time is the opposite of that of the oxygen uptake ($dot{VO2}$) vs time. Since the oxygen uptake is monotone increasing for a short run, we prove that the velocity is exponentially increasing to its maximum and then decreasing. For longer races, the oxygen uptake has an increasing start and a decreasing end and this accounts for the change of velocity profiles. Numerical simulations are compared to timesplits from real races in world championships for 100m, 400m and 800m and the curves match quite well.
This manuscript is a shorthand version of my talk given at Odessa Gamov School on Astronomy, Cosmology and Beyond (22-28 August 2011, Odessa, Ukraine). Within this note we very briefly review the main achievements, new results and open problems in neutrino physics of today.
This is Chapter 1 in the book General Relativity and Gravitation: A Centennial Perspective, Edited by Abhay Ashtekar (Editor in Chief), Beverly Berger, James Isenberg, Malcolm MacCallum. Publisher: Cambridge University Press (June, 2015). It gives a
survey of themes that have been developed during the 100 years of progress in general relativity theory.
In each rowing sport, the oars have their very own characteristics most of the time selected through a long time experience. Here we address experimentally and theoretically the problem of rowing efficiency as function of row lengths and blades sizes
. In contrast with previous studies which consider imposed kinematics, we set an imposed force framework which is closer to human constraints. We find that optimal row lengths and blades sizes depend on sports and athletes strength, and provide an optimisation scheme.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
