THE PHYSICS of TIMLESSNESS Dr
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On the Emergence of Time in Quantum Gravity
Imperial/TP/98–99/23 On the Emergence of Time in Quantum Gravity1 J. Butterfield2 All Souls College Oxford OX1 4AL and C.J. Isham3 The Blackett Laboratory Imperial College of Science, Technology & Medicine South Kensington London SW7 2BZ 13 December 1998 Abstract We discuss from a philosophical perspective the way in which the normal concept of time might be said to ‘emerge’ in a quantum the- ory of gravity. After an introduction, we briefly discuss the notion of arXiv:gr-qc/9901024v1 8 Jan 1999 emergence, without regard to time (Section 2). We then introduce the search for a quantum theory of gravity (Section 3); and review some general interpretative issues about space, time and matter (Section 4). We then discuss the emergence of time in simple quantum ge- ometrodynamics, and in the Euclidean approach (Section 5). Section 6 concludes. 1To appear in The Arguments of Time, ed. J. Butterfield, Oxford University Press, 1999. 2email: [email protected]; jeremy.butterfi[email protected] 3email: [email protected] 1 Introduction The discovery of a satisfactory quantum theory of gravity has been widely regarded as the Holy Grail of theoretical physics for some forty years. In this essay, we will discuss a philosophical aspect of the search for such a theory that bears on our understanding of time: namely, the senses in which our standard ideas of time, and more generally spacetime, might be not fundamental to reality, but instead ‘emergent’ as an approximately valid concept on sufficiently large scales. In taking up this topic, our aim in part is to advertise to philosophers of time an unexplored area that promises to be fruitful. -
A More Direct Representation for Complex Relativity
A more direct representation for complex relativity D.H. Delphenich ∗∗∗ Physics Department, Bethany College, Lindsborg, KS 67456, USA Received 22 Nov 2006, revised 5 July 2007, accepted 5 July 2007 by F. W. Hehl Key words Complex relativity, pre-metric electromagnetism, almost-complex structures, 3- spinors. PACS 02.10.Xm, 02.40.Dr, 03.50.De, 04.50.+h An alternative to the representation of complex relativity by self-dual complex 2-forms on the spacetime manifold is presented by assuming that the bundle of real 2-forms is given an almost- complex structure. From this, one can define a complex orthogonal structure on the bundle of 2- forms, which results in a more direct representation of the complex orthogonal group in three complex dimensions. The geometrical foundations of general relativity are then presented in terms of the bundle of oriented complex orthogonal 3-frames on the bundle of 2-forms in a manner that essentially parallels their construction in terms of self-dual complex 2-forms. It is shown that one can still discuss the Debever-Penrose classification of the Riemannian curvature tensor in terms of the representation presented here. Contents 1 Introduction …………………………………………………………………………. 1 2 The complex orthogonal group …………………………………………………….. 3 3 The geometry of bivectors ………………………………………………………….. 4 3.1 Real vector space structure on A 2……………………………………………….. 5 3.2 Complex vector space structure on A 2…………………………………………... 8 3.3 Relationship to the formalism of self-dual bivectors……………………………. 12 4 Associated principal bundles for the vector bundle of 2-forms ………………….. 16 5 Levi-Civita connection on the bundle SO (3, 1)( M)………………………………… 19 6 Levi-Civita connection on the bundle SO (3; C)( M)………………………………. -
On the Rational Relationship Between Heisenberg Principle and General
CORE Metadata, citation and similar papers at core.ac.uk Provided by CERN Document Server On the Rational Relationship between Heisenberg Principle and General Relativity Xiao Jianhua Henan Polytechnic University, Jiaozuo City, Henan, P.R.C. 454000 Abstract: The research shows that the Heisenberg principle is the logic results of general relativity principle. If inertia coordinator system is used, the general relativity will logically be derived from the Heisenberg principle. The intrinsic relation between the quantum mechanics and general relativity is broken by introducing pure-imaginary time to explain the Lorentz transformation. Therefore, this research shows a way to establish an unified field theory of physics. PACS: 01.55.+b, 03.65.-w, 04.20.-q, 04.20.Ky Keywords: Heisenberg principle, general relativity, commoving coordinator, Riemannian geometry, gauge field 1. Introduction There are many documents to treat the relationship between the Newton mechanics and general relativity. There are also many documents to treat the relationship between the quantum mechanics and general relativity. For some researchers, the related research shows that an unified field theory be possible. For others, the actual efforts to establish an unified field theory for physics have shown that such an unified field theory is totally non-possible. The physics world is divided into three kingdoms. Hence, the title of this paper may make the reader think: See! Another nut! However, the unification of matter motion is the basic relieves for science researchers. The real problem is to find the way. This is the topic of this paper. The paper will firstly derive the Heisenberg principle from general relativity principle. -
How Long Is a Year.Pdf
How Long Is A Year? Dr. Bryan Mendez Space Sciences Laboratory UC Berkeley Keeping Time The basic unit of time is a Day. Different starting points: • Sunrise, • Noon, • Sunset, • Midnight tied to the Sun’s motion. Universal Time uses midnight as the starting point of a day. Length: sunrise to sunrise, sunset to sunset? Day Noon to noon – The seasonal motion of the Sun changes its rise and set times, so sunrise to sunrise would be a variable measure. Noon to noon is far more constant. Noon: time of the Sun’s transit of the meridian Stellarium View and measure a day Day Aday is caused by Earth’s motion: spinning on an axis and orbiting around the Sun. Earth’s spin is very regular (daily variations on the order of a few milliseconds, due to internal rearrangement of Earth’s mass and external gravitational forces primarily from the Moon and Sun). Synodic Day Noon to noon = synodic or solar day (point 1 to 3). This is not the time for one complete spin of Earth (1 to 2). Because Earth also orbits at the same time as it is spinning, it takes a little extra time for the Sun to come back to noon after one complete spin. Because the orbit is elliptical, when Earth is closest to the Sun it is moving faster, and it takes longer to bring the Sun back around to noon. When Earth is farther it moves slower and it takes less time to rotate the Sun back to noon. Mean Solar Day is an average of the amount time it takes to go from noon to noon throughout an orbit = 24 Hours Real solar day varies by up to 30 seconds depending on the time of year. -
The Philosophy and Physics of Time Travel: the Possibility of Time Travel
University of Minnesota Morris Digital Well University of Minnesota Morris Digital Well Honors Capstone Projects Student Scholarship 2017 The Philosophy and Physics of Time Travel: The Possibility of Time Travel Ramitha Rupasinghe University of Minnesota, Morris, [email protected] Follow this and additional works at: https://digitalcommons.morris.umn.edu/honors Part of the Philosophy Commons, and the Physics Commons Recommended Citation Rupasinghe, Ramitha, "The Philosophy and Physics of Time Travel: The Possibility of Time Travel" (2017). Honors Capstone Projects. 1. https://digitalcommons.morris.umn.edu/honors/1 This Paper is brought to you for free and open access by the Student Scholarship at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Honors Capstone Projects by an authorized administrator of University of Minnesota Morris Digital Well. For more information, please contact [email protected]. The Philosophy and Physics of Time Travel: The possibility of time travel Ramitha Rupasinghe IS 4994H - Honors Capstone Project Defense Panel – Pieranna Garavaso, Michael Korth, James Togeas University of Minnesota, Morris Spring 2017 1. Introduction Time is mysterious. Philosophers and scientists have pondered the question of what time might be for centuries and yet till this day, we don’t know what it is. Everyone talks about time, in fact, it’s the most common noun per the Oxford Dictionary. It’s in everything from history to music to culture. Despite time’s mysterious nature there are a lot of things that we can discuss in a logical manner. Time travel on the other hand is even more mysterious. -
Sidereal Time 1 Sidereal Time
Sidereal time 1 Sidereal time Sidereal time (pronounced /saɪˈdɪəri.əl/) is a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky. Just as the Sun and Moon appear to rise in the east and set in the west, so do the stars. A sidereal day is approximately 23 hours, 56 minutes, 4.091 seconds (23.93447 hours or 0.99726957 SI days), corresponding to the time it takes for the Earth to complete one rotation relative to the vernal equinox. The vernal equinox itself precesses very slowly in a westward direction relative to the fixed stars, completing one revolution every 26,000 years approximately. As a consequence, the misnamed sidereal day, as "sidereal" is derived from the Latin sidus meaning "star", is some 0.008 seconds shorter than the earth's period of rotation relative to the fixed stars. The longer true sidereal period is called a stellar day by the International Earth Rotation and Reference Systems Service (IERS). It is also referred to as the sidereal period of rotation. The direction from the Earth to the Sun is constantly changing (because the Earth revolves around the Sun over the course of a year), but the directions from the Earth to the distant stars do not change nearly as much. Therefore the cycle of the apparent motion of the stars around the Earth has a period that is not quite the same as the 24-hour average length of the solar day. Maps of the stars in the night sky usually make use of declination and right ascension as coordinates. -
Governing the Time of the World Written by Tim Stevens
Governing the Time of the World Written by Tim Stevens This PDF is auto-generated for reference only. As such, it may contain some conversion errors and/or missing information. For all formal use please refer to the official version on the website, as linked below. Governing the Time of the World https://www.e-ir.info/2016/08/07/governing-the-time-of-the-world/ TIM STEVENS, AUG 7 2016 This is an excerpt from Time, Temporality and Global Politics – an E-IR Edited Collection. Available now on Amazon (UK, USA, Ca, Ger, Fra), in all good book stores, and via a free PDF download. Find out more about E-IR’s range of open access books here Recent scholarship in International Relations (IR) is concerned with how political actors conceive of time and experience temporality and, specifically, how these ontological and epistemological considerations affect political theory and practice (Hutchings 2008; Stevens 2016). Drawing upon diverse empirical and theoretical resources, it emphasises both the political nature of ‘time’ and the temporalities of politics. This chronopolitical sensitivity augments our understanding of international relations as practices whose temporal dimensions are as fundamental to their operations as those revealed by more established critiques of spatiality, materiality and discourse (see also Klinke 2013). This transforms our understanding of time as a mere backdrop to ‘history’ and other core concerns of IR (Kütting 2001) and provides opportunities to reflect upon the constitutive role of time in IR theory itself (Berenskoetter 2011; Hom and Steele 2010; Hutchings 2007; McIntosh 2015). One strand of IR scholarship problematises the historical emergence of a hegemonic global time that subsumed within it local and indigenous times to become the time by which global trade and communications are transacted (Hom 2010, 2012). -
Developing a Critical Horology to Rethink the Potential of Clock Time’ in New Formations (Special Issue: Timing Transformations)
This is the final accepted version of this article. Bastian, M. (forthcoming) ‘Liberating clocks: developing a critical horology to rethink the potential of clock time’ in New Formations (Special Issue: Timing Transformations). Liberating clocks: developing a critical horology to rethink the potential of clock time Michelle Bastian [email protected] Introduction When trying to imagine a new time, a transformed time, a way of living time that is inclusive, sustainable or socially-just – a liberatory time – it is unlikely that a clock will spring to mind. If anything, the clock has become the symbol of all that 1 has gone wrong with our relationship to time. This general mistrust of the clock is well-captured by literary theorist Jesse Matz who observes: Clock time was the false metric against which Henri Bergson and others defined the truth of human time. Modernists made clocks the target of their iconoclasm, staging clocks’ destruction (smashing watches, like Quentin in The Sound and the Fury [1929]) or (like Dali) just melting away, and cultural theorists before and after Foucault have founded cultural critique on the premise that clock time destroys humanity.1 Thus, across a wide range of cultural forms, including philosophy, cultural theory, literature and art, the figure of the clock has drawn suspicion, censure and outright hostility. When we compare this to attitudes towards maps however – which are often thought of as spatial counterparts to clocks – we find a remarkably differently picture. While maps have 1 Jesse Matz, 'How to Do Time with Texts', American Literary History, 21, 4 (2009), 836-44, quotation p836. -
The No-Boundary Proposal Via the Five-Dimensional Friedmann
The no-boundary proposal via the five-dimensional Friedmann-Lemaˆıtre-Robertson-Walker model Peter K.F. Kuhfittig* and Vance D. Gladney* ∗Department of Mathematics, Milwaukee School of Engineering, Milwaukee, Wisconsin 53202-3109, USA Abstract Hawking’s proposal that the Universe has no temporal boundary and hence no be- ginning depends on the notion of imaginary time and is usually referred to as the no-boundary proposal. This paper discusses a simple alternative approach by means of the five-dimensional Friedmann-Lemaˆıtre-Robertson-Walker model. PAC numbers: 04.20.-q, 04.50.+h Keywords: no-boundary proposal, FLRW model 1 Introduction It is well known that Stephen Hawking introduced the no-boundary proposal using the concept of imaginary time, making up what is called Euclidean spacetime [1]. While ordi- nary time would still have a big-bang singularity, imaginary time avoids this singularity, implying that the Universe has no temporal boundary and hence no beginning. By elim- inating the singularity, the Universe becomes self-contained in the sense that one would arXiv:1510.07311v2 [gr-qc] 7 Jan 2016 not have to appeal to something outside the Universe to determine how the Universe began. Given that imaginary time is orthogonal to ordinary time, one could view imaginary time as an extra dimension. The existence of an extra dimension suggests a different start- ing point, the five-dimensional Friedmann-Lemaˆıtre-Robertson-Walker model (FLRW) [2]. This model produces a simple alternative version of the no-boundary proposal. 2 The FLRW model Let us recall the FLRW model in the usual four dimensions [3]: dr2 ds2 = dt2 + a2(t) + r2(dθ2 + sin2θdφ2) , (1) − 1 Kr2 − ∗kuhfi[email protected] 1 where a2(t) is a scale factor. -
Swinging in Imaginary Time More on the Not-So-Simple Pendulum
GENERAL ARTICLE Swinging in Imaginary Time More on the Not-So-Simple Pendulum Cihan Saclioglu When the small angle approximation is not made, the exact solution of the simple pendulum is a Jacobian elliptic function with one real and one imaginary period. Far from being a physically meaningless mathematical curiosity, the second period represents the imaginary time the pendu- lum takes to swing upwards and tunnel through Cihan Saclioglu teaches the potential barrier in the semi-classical WKB physics at Sabanci approximation1 in quantum mechanics. The tun- University, Istanbul, neling here provides a simple illustration of simi- Turkey. His research lar phenomena in Yang{Mills theories describing interests include solutions of Yang–Mills, Einstein weak and strong interactions. and Seiberg–Witten equations and group 1. Introduction theoretical aspects of string theory. Consider a point mass m at the end of a rigid massless stick of length l. The acceleration due to gravity is g and the oscillatory motion is con¯ned to a vertical plane. Denoting the angular displacement of the stick from the 1When the exact quantum me- vertical by Á and taking the gravitational potential to chanical calculation of the tun- be zero at the bottom, the constant total energy E is neling probability for an arbitrary given by potential U(x) is impracticable, the Wentzel–Kramers–Brillouin 1 dÁ 2 approach, invented indepen- E = ml2 + mgl(1 cos Á) dently by all three authors in the 2 dt ¡ µ ¶ same year as the Schrödinger = mgl(1 cos Á0); (1) equation, provides an approxi- ¡ mate answer. 2 where Á0 is the maximum angle. -
TIME 1. Introduction 2. Time Scales
TIME 1. Introduction The TCS requires access to time in various forms and accuracies. This document briefly explains the various time scale, illustrate the mean to obtain the time, and discusses the TCS implementation. 2. Time scales International Atomic Time (TIA) is a man-made, laboratory timescale. Its units the SI seconds which is based on the frequency of the cesium-133 atom. TAI is the International Atomic Time scale, a statistical timescale based on a large number of atomic clocks. Coordinated Universal Time (UTC) – UTC is the basis of civil timekeeping. The UTC uses the SI second, which is an atomic time, as it fundamental unit. The UTC is kept in time with the Earth rotation. However, the rate of the Earth rotation is not uniform (with respect to atomic time). To compensate a leap second is added usually at the end of June or December about every 18 months. Also the earth is divided in to standard-time zones, and UTC differs by an integral number of hours between time zones (parts of Canada and Australia differ by n+0.5 hours). You local time is UTC adjusted by your timezone offset. Universal Time (UT1) – Universal time or, more specifically UT1, is counted from 0 hours at midnight, with unit of duration the mean solar day, defined to be as uniform as possible despite variations in the rotation of the Earth. It is observed as the diurnal motion of stars or extraterrestrial radio sources. It is continuous (no leap second), but has a variable rate due the Earth’s non-uniform rotational period. -
On Stability of Physical Systems in a Complex Plane
ON STABILITY OF PHYSICAL SYSTEMS IN A COMPLEX PLANE V.V. Lyahov, V.M. Neshchadim 1. Introduction Complex numbers have fully come into common use in mathematics from the very moment of their discovery. Let's mention only one their property – the property of algebraic closedness of the field of complex numbers. The physics even now is in the stage of half-recognizing of complex numbers. On the one hand, the physics, using mathematical means, manipulates imaginaries; on the other hand, common sense says that all observable quantities should be associated with real numbers. Complex calculus should be only an auxiliary, mathematically formal tool. The line of reasoning of a modern physicist is as follows: “We live in the real world; therefore, all quantities should be featured by real numbers”. This statement seems to be completely natural without any additional argumentation. Such situation is an example of paradigm and is taken for granted by scientists. It may be said that the advancement of science confirms this thesis. But it seems that there are also opposite examples. Imaginary timeτ=i⋅ct is introduced into the relativity theory, and only in this form together with three spatial coordinates it forms a four-dimensional space-time. The fourth axis of space-time is an imaginary quantity. In the theory of relativity, on the one hand, it is always underlined that imaginary time is of conditional nature, but, on the other hand, it is also always noted that a deeply essential linkage between space and time was discovered for the first time. The basic object of the quantum mechanics - a complex-valued wave function is referred to as not being of any physical sense, but the square of this function has physical sense.