Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Dimensionless Groups in Fluid Mechanics01:15

Dimensionless Groups in Fluid Mechanics

Dimensionless groups in fluid mechanics provide simplified ratios that help analyze fluid behavior without relying on specific units. The Reynolds number (Re), which represents the ratio of inertial to viscous forces, distinguishes between laminar and turbulent flows, making it essential in the design of pipelines and aerodynamic surfaces. The Froude number (Fr), the ratio of inertial to gravitational forces, is particularly useful in predicting wave formation and hydraulic jumps in...
Gravitation Between Spherically Symmetric Masses01:14

Gravitation Between Spherically Symmetric Masses

The gravitational potential energy between two spherically symmetric bodies can be calculated from the masses and the distance between the bodies, assuming that the center of mass is concentrated at the respective centers of the bodies.
Gravity between Spherical Bodies01:27

Gravity between Spherical Bodies

Newton's law of gravitation describes the gravitational force between any two point masses. However, for extended spherical objects like the Earth, the Moon, and other planets, the law holds with an assumption that masses of spherical objects are concentrated at their respective centers.
This assumption can be proved easily by showing that the expression for gravitational potential energy between a hollow sphere of mass (M) and a point mass (m) is the same as it would be for a pair of extended...
Space-Time Curvature and the General Theory of Relativity01:17

Space-Time Curvature and the General Theory of Relativity

In 1905, Albert Einstein published his special theory of relativity. According to this theory, no matter in the universe can attain a speed greater than the speed of light in a vacuum, which thus serves as the speed limit of the universe.
This has been verified in many experiments. However, space and time are no longer absolute. Two observers moving relative to one another do not agree on the length of objects or the passage of time. The mechanics of objects based on Newton's laws of motion,...
Dimensional Analysis01:23

Dimensional Analysis

Dimensional analysis is a powerful tool that is used in physics and engineering to understand and predict the behavior of physical systems. The basic idea behind dimensional analysis is to express physical quantities in terms of fundamental dimensions such as the mass, length, and time. Derived dimensions like the velocity, acceleration, and force are derived from the combinations of these fundamental dimensions.
Dimensional analysis allows us to analyze and compare physical quantities on a...
Dimensional Analysis02:19

Dimensional Analysis

The concept of dimension is important because every mathematical equation linking physical quantities must be dimensionally consistent, implying that mathematical equations must meet the following two rules. The first rule is that, in an equation, the expressions on each side of the equal sign must have the same dimensions. This is fairly intuitive since we can only add or subtract quantities of the same type (dimension). The second rule states that, in an equation, the arguments of any of the...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Introduction to the special issue dedicated to Michael J. Duff FRS on the occasion of his 70th birthday.

Proceedings. Mathematical, physical, and engineering sciences·2022
Same author

Weyl Double Copy for Gravitational Waves.

Physical review letters·2021
Same author

Positive Energy Functional for Massless Scalars in Rotating Black Hole Backgrounds of Maximal Ungauged Supergravity.

Physical review letters·2020
Same author

A pilot investigation on the effects of combination transcranial direct current stimulation and speed of processing cognitive remediation therapy on simulated driving behavior in older adults with HIV.

Transportation research. Part F, Traffic psychology and behaviour·2019
Same author

Black holes in higher derivative gravity.

Physical review letters·2015
Same author

Evaluation of efficacy of mineral oil, charcoal, and smectite in a rat model of equine cantharidin toxicosis.

Journal of veterinary internal medicine·2013
Same journal

Erratum: Bacterial Turbulence at Compressible Fluid Interfaces [Phys. Rev. Lett. 136, 138301 (2026)].

Physical review letters·2026
Same journal

Unveiling Light-Quark Yukawa Flavor Structure via Dihadron Fragmentation at Lepton Colliders.

Physical review letters·2026
Same journal

Adaptable Route to Fast Coherent State Transport via Bang-Bang-Bang Protocols.

Physical review letters·2026
Same journal

Topological Transition and Emergence of Elasticity of Dislocation in Skyrmion Lattice: Beyond Kittel's Magnetic-Polar Analogy.

Physical review letters·2026
Same journal

Pound-Drever-Hall Method for Superconducting-Qubit Readout.

Physical review letters·2026
Same journal

Coupling a ^{73}Ge Nuclear Spin to an Electrostatically Defined Quantum Dot in Silicon.

Physical review letters·2026
See all related articles

Related Experiment Video

Updated: Jun 1, 2026

Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mixing Technology
13:59

Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mixing Technology

Published on: November 13, 2014

Critical gravity in four dimensions.

H Lü1, C N Pope

  • 1China Economics and Management Academy, Central University of Finance and Economics, Beijing, China.

Physical Review Letters
|June 4, 2011
PubMed
Summary
This summary is machine-generated.

Researchers explored four-dimensional gravity theories, finding a critical theory that eliminates massive modes. This critical theory offers a potential toy model for quantum gravity, with vanishing black hole mass and entropy.

More Related Videos

Coherence between Brain Cortical Function and Neurocognitive Performance during Changed Gravity Conditions
12:29

Coherence between Brain Cortical Function and Neurocognitive Performance during Changed Gravity Conditions

Published on: May 23, 2011

Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement
09:57

Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement

Published on: January 20, 2022

Related Experiment Videos

Last Updated: Jun 1, 2026

Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mixing Technology
13:59

Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mixing Technology

Published on: November 13, 2014

Coherence between Brain Cortical Function and Neurocognitive Performance during Changed Gravity Conditions
12:29

Coherence between Brain Cortical Function and Neurocognitive Performance during Changed Gravity Conditions

Published on: May 23, 2011

Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement
09:57

Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement

Published on: January 20, 2022

Area of Science:

  • Theoretical Physics
  • Quantum Gravity
  • General Relativity

Background:

  • Einstein-Herglotz gravity theories are generally not renormalizable.
  • Curvature-squared terms can be added to Einstein-Hilbert actions to improve renormalizability.
  • Cosmological constants play a role in gravitational theories.

Purpose of the Study:

  • To investigate four-dimensional gravity theories with curvature-squared terms.
  • To determine if a critical theory can be constructed by eliminating massive modes.
  • To explore the potential of this critical theory as a quantum gravity model.

Main Methods:

  • Studying four-dimensional gravity theories with Einstein-Hilbert and curvature-squared terms.
  • Analyzing the conditions for eliminating massive scalar and spin-2 modes.
  • Investigating the properties of resulting massless gravitons and logarithmic modes.

Main Results:

  • A critical theory is identified where massive modes are eliminated, and the spin-2 mode becomes massless.
  • The on-shell energy of the remaining massless gravitons vanishes.
  • Logarithmic spin-2 modes with positive energy and vanishing black hole mass/entropy are found.

Conclusions:

  • The critical theory serves as a four-dimensional analogue of massive gravity theories in lower dimensions.
  • This critical theory presents a consistent, albeit simplified, model for quantum gravity in four dimensions.
  • The vanishing energy and black hole properties suggest unique characteristics of this quantum gravity model.