G. Jordan Maclay
RESEARCH IN QUANTUM FLUCTUATIONS
Articles in the Popular Press
"Quantum Starship hits
the slow lane," by M.
Chow, New Scientist Magazine, pp 20-21, 5/24/2003.
Based on
our article about a spacecraft that accelerates by pushing on the vacuum, and
extract energy
from the
vacuum to operate.
"Space
at Warp Speed" by Mariette DiChristina, Popular Science,
pp46-51, 5/2001. About NASA
Breakthrough
Propulsion Program, and our role in it.
ZPV
Background by Jordan Maclay, Quantum Fields LLC. Some general
ideas on vacuum energy.
"Energy
Unlimited," by Henry Bortman for New
Scientist Magazine, pp32-34, 1/22/2000. Feature
article on
our vacuum energy project using MEMS devices to measure vacuum energy.
Reviews by our Peers
In 1995 and 1998 Prof. Maclay
and his students published the first models of a microelectromechanical system
(MEMS) with Casimir forces. In their extensive and authoritative review
book "Advances in the Casimir Effect," Oxford University Press, 2009,
authors Bordag, Klimchitskaya,
Mohideen, and Mostepanenko state
that these papers [#15, #16
below] "drew the attention of the MEMS community to the fact that
the Casimir effect needs to be considered as a vital factor in the future
design of MEMS.
The results obtained served as
a starting point for future developments of applications of the Casimir effect
in MEMS systems.. It was revealed that the Casimir
effect might be the critical factor in the stiction failure of MEMS."
In their
review article entitled "Details of the Casimir Effect and its
computation," American Journal of Physics, 59, 8, pp. 711-719(1991),
authors E. Elizaide and A. Romero state: " The paper
[#14 below] by L.S. Brown and G. J. Maclay, published 21 years after the work
of Casimir, was especially significant from a theoretical point of view, a kind
of milestone on the road leading to the modern Quantum Field Theory interpretation
of the Casimir effect. For the first time, it contains the local interpretation
of the Casimir effect, in terms of vacuum energy and vacuum pressure…for the
first time the calculation involved
the Zeta
function procedure…which has evolved into the most elegant, simple, and
mathematically rigorous way of defining regularized vacuum energy densities in
situations that nowadays very much generalize the original case considered by
Casimir.”
G. Jordan Maclay
SCIENTIFIC ARTICLES
Publications
about vacuum energy, vacuum fluctuations or zero point
energy, Casimir forces
24. “The Role of Vacuum Fluctuations and Symmetry in the
Hydrogen Atom in Quantum Mechanics and Stochastic Electrodynamics,”
J. Maclay, Atoms 7, 39 (2019).
Vacuum fluctuations play a pivotal role in the hydrogen atom and are
dealt with quite differently in quantum mechanics and stochastic
electrodynamics, which postulates that the vacuum field is real and that this
real stochastic field leads to the stability of the H atom. Computations to date do not support this
latter notion. In quantum mechanics, the
symmetry of the H atom leads directly to the solutions for the wavefunctions
and the energy levels.
23. “Effect of quantum and thermal jitter on the feasibility of Bekenstein’s proposed experiment to search for Planck-scale
signals,” J.
Maclay, S. Wadood, E. Black, and P. Milonni, Phys. Rev. D 99,
124053 (2019).
This
paper analyzes a ingenious proposal by Jacob Beckenstein from Princeton, who started the field of the
thermodynamics of black holes, that one might detect the quantum foam proposed
by Wheeler by considering anomalous reflection of light from a small piece of
glass that would occur when the absorption of the light would cause the glass
to move less than a Planck length. We
were very fortunate to have the comments and suggestions on Nobel Laureate
Rainer Weiss on this paper.
22.
“Testing a Quantum Inequality with a Meta-analysis of Data for Squeezed
Light,” J. Maclay and E. Davis, Foundations of
Physics, 49, 797 (2019).
This paper is the only
experimental test to date of a Quantum Inequality (QI), which is a restriction
from quantum field theory on the concentration of negative vacuum energy over
time and space. Using the squeezed light
data collected over the last 20 years, we find that the restriction on negative
vacuum energy is violated by most of the data, bringing into question the
significance of quantum inequalities in quantum theory as well as the challenge
of experimental verification of quantum inequalities. LOTS of negative vacuum energy is needed to
make a wormhole or a warp drive and if QI are not applicable, then quantum
theory may not prohibit these unusual phenomena.
21. “The Role of the Quantum Vacuum in Space Travel,”
J. Maclay, Journal of the British Interplanetary Society 68, 86
(2015).
This
paper discusses the potential role of vacuum energy in space travel, detailing
the challenges and properties of vacuum energy and the restrictions on its
use. It discusses different approaches
to utilizing vacuum energy.
20. "Gedanken experiments with
Casimir forces and vacuum energy" J. Maclay, Physical Review A
82, 032106 (2010).
This rather
philosophical article presents a series of gedanken
or thought experiments with quantum vacuum energy and gravity. Einstein
was a master of gedanken experiments,
and developed his theories of relativity using them. The
first gedanken experiment shows the impossibility of
making a fixed surface that will be accelerated by the free vacuum
fluctuations. Other gedanken experiments show
that changes in vacuum energy ΔE = Mc2 generate a gravitational field
just like the corresponding mass M. Similarly, the gravitational field of
a normal mass will attract the vacuum energy as if it were the equivalent mass
M. The only difference about vacuum energy from any other form of energy,
and it is an important one, is that ΔE can be NEGATIVE, meaning below the vacuum energy
density of empty space. IF the vacuum energy is negative, it acts like a
negative mass, and would be repelled by a normal mass! A negative mass
object would rise in the earths gravitational field! Unfortunately
no one knows how to make such an object!
The last gedanken experiment is about a box that shields
the contents from gravitational fields of matter outside the box. You
can't buy one of these, but it is fun to think about its properties, and what
you might be able to do with it, for example launch a rocket.
19. "Thrusting
Against the Quantum Vacuum" , J. Maclay, Chapter 12 in the book Frontiers of
Propulsion Science, edited by Marc Milles and Eric Davis,
published by American Institute of Aeronautics and Astronautics, Reston VA
(2009). This groundbreaking volume has many interesting cutting edge papers. This paper is a continuation of
the work that appeared in # 18 below, Gedanken
Spacecraft published with legend Bob Forward in 2004.
18. "A Gedanken spacecraft
that operates using the quantum vacuum (Dynamic Casimir effect),"
J. Maclay and R.L. Forward, Foundations of Physics 34, 477 (2004).
The above paper describes the first spacecraft that operates totally on
energy from the quantum vacuum, using the excited vacuum for its drive.
It doesn’t go very fast, but we still call it the Casimir Drive. The
paper discusses the latest scientific ideas about extraction of energy from the
vacuum. This is the last paper by coauthor Bob Forward, visionary science
fiction author and physicist, before he died. Science writer Martin Chow
described this paper in the New Scientist "Quantum
Starship hits the slow lane."
17.
J. Maclay, "The role of Quantum Vacuum forces in
microelectromechanical systems"
This paper gives some fun speculations about the future of the relationship
between vacuum energy and MEMS.
16. "The
Anharmonic Casimir Oscillator," M. Serry, D. Walliser, J.
Maclay, IEEE-ASME Journal of Microelectromechanical
Systems 4,193-205, 1995.
This classic paper is the first paper that proposed and studied a dynamical
system with Casimir forces in it! It is an elegant study, and is the
theoretical model implemented in the first MEMS device with Casimir forces made
by Frederico Capasso, who
wears some great ties, and collaborators when he was at Bell Labs.
15. "The
role of the casimir effect in the static deflection
and stiction of membrane strips in microelectromechanical systems (MEMS),"
M. Serry, D. Walliser, J.
Maclay Journal of Applied Physics 84, 2501-2506 (1998).
Another first in the calculation of the effect of Casimir forces in MEMS
systems. This showed for the first time that Casimir forces would cause
the distortion of microfabricated membranes.
14.
L. Brown and J. Maclay, "Vacuum stress between conducting plates: an image
solution," Physical Review 184, 1791-1800 (1969).
Here it is, an oldie but goodie. This lucid paper revolutionized the
computation of vacuum energy and vacuum forces. It was the first time
they were computed as a function of position (stress-energy tensor). The
methods developed became the foundation of modern vacuum energy computations.
Done with my insightful thesis advisor, Lowell Brown, a student of Nobel
Laureate Julian Schwinger, both very elegant in their physics.
13.
J. Maclay, P. Milonni, "Quantized-field
description of light in negative-index media," Optics
Communications 228, 161-165, 2003
This is the
first description of media with a negative index of refraction of light in
terms of quantized fields. All normal media have a positive index or
refraction, so these media show some unusual properties, like a Doppler shift
that is in the opposite direction from the normal shift. This was written
with my good friend Peter Milonni, quantum physicist
extraordinaire, who has just published An
Introduction to Quantum Optics and Quantum Fluctuations, Oxford University
Press (2019). He also wrote the Quantum Vacuum, An Introduction to
Quantum Field Electrodynamics, Academic Press. These books provide the best introduction
to quantum physics and the role of quantum fluctuations you can get, with lots
of physical insight and clear mathematics.
12.
J. Maclay, P. Milonni, H. Fearn,
"Of some theoretical significance: implications of Casimir
effects," European Journal of Physics 22, 463-469
(2001)
A great review of Casimir effects and vacuum energy, very readable, written in
honor of Casimir’s death. Discusses the role of vacuum energy and Casimir
forces in many areas, from the structure of the universe to microfabricated
devices. Easy read for the nonspecialist.
11.
J. Maclay, "An analysis of vacuum fluctuation energy and
Casimir forces in conductive rectangular cavities," Phys. Rev.
A. 61, 052110 (2000).
Summarizes
key ideas in vacuum energy calculations for geometries that are not just the
old parallel plate geometry. Good discussion of the unexpected features
of vacuum energy and vacuum forces in little metal boxes (what we call
rectangular cavities), such as the possibility of inward forces on one side and
outward forces or zero force on other sides. Nice figures.
10.
J. Maclay, "A design manual for micromachines using Casimir
forces: preliminary considerations," PROCEEDINGS of STAIF-00 (Space Technology and Applications International Forum-2000,
Albuquerque, NM, January, 1999), edited by M.S. El-Genk, AIP Conference
Proceedings, American Institute of Physics, New York 2000. Published in
hardcopy and CD-ROM by AIP.
This readable article talks about some simple ideas in the design of
micromachines that are based on vacuum energy. It also points out the
problems with some common ideas and why they don’t work.
9. J.
Maclay, "Unusual properties of conductive rectangular cavities in the
zero point electromagnetic field: Resolving Forward's Casimir energy extraction
cycle paradox," PROCEEDINGS of STAIF-99 (Space Technology and Applications International Forum-1999,
Albuquerque, NM, January, 1999), edited by M.S. El-Genk, AIP Conference
Proceedings 458, American Institute of Physics, New York 1999. Published in
hardcopy and CD-ROM by AIP.
This article presents the explanation of why Bob Forwards idea for extracting
energy from the vacuum does not work. Usually we think that if the energy
density in a box is greater than the energy density outside the box, that there
will be an outward force on the walls of the box, which is what Bob’s idea was
based on. However, for vacuum energy this it
not true!
8. J.
Maclay, C. Villarreal, "A model for Casimir Forces in closed cavities with
finite conductivity," presented at the symposium "Casimir Forces:
Recent Results in experiment and theory," Harvard-Cambridge Center for
astrophysics, Harvard University, Cambridge, MA, Nov. 14, 2002. The talk
is available online at ITAMP website: http://itamp.harvard.edu/itamp_online.html.
This talk focuses on the large gap between the vacuum forces or Casimir
forces theoreticians calculate and what experimentalists measure.
Suggestions are made on ways to narrow the gap.
7. J.
Maclay, J. Hammer, M. George, R. Ilic, Q. Leonard, R.
Clark, "Measurement of repulsive quantum vacuum
forces," AIAA-2001-3359, AIAA/ASME/SAE/ASEE 37th Joint
Propulsion Conference, Salt Lake City, 2001 Descriptions of experiments
designed to measure repulsive forces.
6. J.
Maclay, J. Hammer, "Vacuum forces in microcavities,"
Seventh International Conference on Squeezed States and Uncertainty Relations,
Boston, MA June 4-6, 2001, Proceedings available online at website:
http://www.physics.umd.edu/robot
Discussion of ideas about Casimir forces in small
boxes and other structures.
5. J.
Maclay, R. Ilic, M. Serry,
P. Neuzil, “Use of AFM (Atomic Force Microscope)
Methods to Measure Variations in Vacuum Energy Density and Vacuum Forces in
Microfabricated Structures,” NASA Breakthrough Propulsion Workshop, Cleveland,
Ohio, May, 1997.
4. F.
Serry, P. Neuzil, R. Vilasuso, and G. J. Maclay, "Air Damping of Resonant
AFM Micro-Cantilevers in the Presence of a Nearby Surface," Proceedings of
the Second International Symposium on Microstructures and Microfabricated
Systems, pp 83-89, Chicago, IL, October, 1995.
3. L.
St. Clair, J. Maclay, "Metal Microbridges to Investigate Quantum
Forces," Proceedings of the Winter Annual Meeting of the ASME, 9 pages,
Chicago, II November, 6-11, 1994.
2. F.
Serry, J. Maclay, "The Casimir Effect in a Model
Microelectromechanical System," Illinois Chapter of the AVS Annual Fall
Meeting, Chicago, IL, September, 1993.
1. R.
Mast, M. Serry, J. Maclay, "Measurement of
Forces in Microcavities due to Quantum Fluctuations," Prog. of 39th
National Symposium of the American Vacuum Society, P. 323, Chicago, November
9-13, 1992.