scholarly journals SPACE-TIME UNCERTAINTY AND NONCOMMUTATIVITY IN STRING THEORY

2001 ◽  
Vol 16 (05) ◽  
pp. 945-955 ◽  
Author(s):  
TAMIAKI YONEYA
Keyword(s):  
Quantum Mechanics ◽  
String Theory ◽  
Uncertainty Principle ◽  
Space Time ◽  
Field Theories ◽  
Time Uncertainty ◽  
Spatial Coordinates ◽  
Temporal And Spatial

We analyze the nature of space-time nonlocality in string theory. After giving a brief overview on the conjecture of the space-time uncertainty principle, a (semi-classical) reformulation of string quantum mechanics, in which the dynamics is represented by the noncommutativity between temporal and spatial coordinates, is outlined. The formalism is then compared to the space-time noncommutative field theories associated with nonzero electric B-fields.

scholarly journals UNITARITY OF NONCOMMUTATIVE FIELD THEORIES FROM STRING THEORY

2003 ◽  
Vol 18 (33n35) ◽  
pp. 2525-2532 ◽  
Author(s):  
ALESSANDRO TORRIELLI
Keyword(s):  
String Theory ◽  
Open String ◽  
Space Time ◽  
Bosonic String ◽  
Field Theories ◽  
Noncommutative Space ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Superstring Theory ◽  
Time Quantum

We improve the study of the lack of perturbative unitarity of noncommutative space-time quantum field theories derived from open string theory in electric backgrounds, enforcing the universality of the mechanism by which a tachyonic branch cut appears when the Seiberg-Witten limit freezes the string in an unstable vacuum. The main example is realized in the context of the on-shell four-tachyon amplitude of the bosonic string, and the dependence of the phenomenon on the brane-worldvolume dimension is analysed. We discuss the possibility of a proof in superstring theory, and finally mention the NCOS limit in this framework.

scholarly journals On the Space–Time Uncertainty Relations of Liouville Strings and D-Branes

1997 ◽  
Vol 12 (27) ◽  
pp. 2029-2035 ◽  
Author(s):  
G. Amelino-Camelia ◽  
N. E. Mavromatos ◽  
John Ellis ◽  
D. V. Nanopoulos
Keyword(s):  
String Theory ◽  
Commutation Relation ◽  
Uncertainty Relation ◽  
Space Time ◽  
Uncertainty Relations ◽  
Time Uncertainty ◽  
Space And Time

Within a Liouville approach to noncritical string theory, we argue for a nontrivial commutation relation between space and time observables, leading to a nonzero space–time uncertainty relation δx δt>0, which vanishes in the limit of weak string coupling.

Heisenberg, Bohr, Robertson, and the Uncertainty Principle

2020 ◽  
pp. 133-156
Author(s):  
Jim Baggott
Keyword(s):  
Quantum Mechanics ◽  
Uncertainty Principle ◽  
Laboratory Experiments ◽  
Space Time ◽  
Spectral Lines ◽  
Planck’S Constant ◽  
Classical Space ◽  
Planck's Constant

From the outset, Heisenberg had resolved to eliminate classical space-time pictures involving particles and waves from the quantum mechanics of the atom. He had wanted to focus instead on the properties actually observed and recorded in laboratory experiments, such as the positions and intensities of spectral lines. Alone in Copenhagen in February 1927, he now pondered on the significance and meaning of such experimental observables. Feeling the need to introduce at least some form of ‘visualizability’, he asked himself some fundamental questions, such as: What do we actually mean when we talk about the position of an electron? He went on to discover the uncertainty principle: the product of the ‘uncertainties’ in certain pairs of variables—called complementary variables—such as position and momentum cannot be smaller than Planck’s constant h (now h / 4π‎).

scholarly journals SPACE–TIME UNCERTAINTY PRINCIPLE FROM BREAKDOWN OF TOPOLOGICAL SYMMETRY

1998 ◽  
Vol 13 (03) ◽  
pp. 203-209 ◽  
Author(s):  
ICHIRO ODA
Keyword(s):  
Uncertainty Principle ◽  
Uncertainty Relation ◽  
Space Time ◽  
Topological Quantum Field Theory ◽  
Time Interval ◽  
Quantum Field ◽  
Higher Symmetry ◽  
Time Uncertainty ◽  
Topological Quantum ◽  
Large N

Starting from topological quantum field theory, we derive space–time uncertainty relation with respect to the time interval and the spatial length proposed by Yoneya through breakdown of topological symmetry in the large-N matrix model. This work suggests that the topological symmetry might be an underlying higher symmetry behind the space–time uncertainty principle of string theory.

Exploration of the unification of fields

2019 ◽  
Vol 32 (3) ◽  
pp. 399-410
Author(s):  
Ge Guangzhou
Keyword(s):  
Black Hole ◽  
Electromagnetic Field ◽  
Quantum Mechanics ◽  
Field Equation ◽  
Uncertainty Principle ◽  
Equivalence Principle ◽  
Space Time ◽  
The State ◽  
State Function ◽  
Tensor Equation

This article may be deemed as an exploration on the unification of fields as well as a discussion of the completeness in physics. This author tended to support the viewpoint of Einstein and believed that the Uncertainty Principle should be in itself incomplete, and that the representation of the state function ψ should not be complete in quantum mechanics. Following a series of discussions, including the hypothesis of a new quantum, the relativity of electromagnetic field, and the general equivalence principle, this author proposes here a new field equation called Hamilton’s tensor equation (HTE). Acting as the complete presentation of Einstein’s field equation and as an extension of Hamilton’s principle, what this new field equation (HTE) has revealed is that the “virtuality” of space‐time, rather than its curvature, is what determines the distribution and movement of matter and energy. Based on this new field equation (HTE), the author has extended the study to include the unification of fields, a model of new particle, and the phenomenon of black hole.

Paradoxes of Nature

2020 ◽  
pp. 87-98
Author(s):  
Demetris Nicolaides
Keyword(s):  
Quantum Mechanics ◽  
Uncertainty Principle ◽  
Apparent Motion ◽  
Space Time ◽  
The Other ◽  
Even Start ◽  
Other Hand ◽  
Logical Paradoxes

Parmenides’s insinuation of an unchanging universe is assertively supported by Zeno with various logical paradoxes that question the very nature of plurality, space, time, and the reality of apparent motion. The dichotomy is his most famous paradox. To begin a trip, say, from here to the door, a traveler must travel the first half of it, but before she does that she must travel half of the first half, and in fact half of that, ad infinitum. Since there will always exist a smaller first half to be traveled first, Zeno questions whether a traveler can ever even start a trip. Zeno’s analysis is logical; on the other hand, things everywhere appear to be moving. Hence, either Zeno’s reasoning is wrong or appearances are deceptive. Empowered by the uncertainty principle of quantum mechanics, it will be argued that, at best, the phenomenon of motion is experimentally unverifiable!

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