Invisibility: Theory and Practice - v2

http://timeandquantummechanics.comInvisibility: Theory & Practice - FOSSCON, Aug 10th 2013
Invisibility:
Theory &
Practice
John Ashmead
Friday, August 9, 13

http://timeandquantummechanics.comInvisibility: Theory & Practice - FOSSCON, Aug 10th 2013
Invisibility:
Theory &
Practice
John Ashmead
Newly updated for
FOSSCON!

Invisibility: Theory & Practice - FOSSCON, Aug 10th, 2013 http://timeandquantummechanics.com
Transparent
Motives

Transparent
Motives
•Wicked cool

Transparent
Motives
•Wicked cool
•Very practical:
not just for war
anymore!

Transparent
Motives
•Wicked cool
•Very practical:
not just for war
anymore!
•And of great
scientiﬁc value

Outline

Outline
•A brief history of
invisibility

Outline
invisibility
•Reﬂections on
materials

Outline
invisibility
•Reﬂections on
materials
•War, peace & the
future

The Invisible
Man
“If a sheet of glass is smashed, Kemp, and beaten into a powder, it
becomes much more visible while it is in the air; it becomes at last an
opaque white powder. This is because the powdering multiplies the
surfaces of the glass at which refraction and reflection occur. In the
sheet of glass there are only two surfaces; in the powder the light is
reflected or refracted by each grain it passes through, and very little
gets right through the powder. But if the white powdered glass is put
into water, it forthwith vanishes. The powdered glass and water have
much the same refractive index; that is, the light undergoes very little
refraction or reflection in passing from one to the other.” -- Griffin
…
“Yes, yes,” said Kemp. “But a man's
not powdered glass!”

Sucker Bet

The last cry you hear
could be “Mimicry”

The last cry you hear
could be “Mimicry”
Yellow
touches
red, you
be dead.
Red
touches
black, eat
Cracker
Jacks.

Spicebush swallowtail

Camouflage
“The soldiers
of France will
never
abandon
their
pantaloons
rouge!”

Camouflage
Modern camouﬂage began in
1915, when, after a crushing
defeat by the Germans, the
French army abandoned their
stylish white gloves and red
pantaloons and enlisted a cadre
of artists to develop stealthier
attire. The U.S. followed suit in
1917. In addition to hand-
painted uniforms, these
camouﬂeurs created false
bridges, decoy tanks, and, as
seen above, paper-mache horse
carcasses that snipers used as
blinds.

Dazzle

Dazzle
•Ships in WWI &
WWII

Dazzle
•Ships in WWI &
WWII
•Confusion to the
enemy

Dazzle
•Ships in WWI &
WWII
•Confusion to the
enemy
•Moral boost at
least

Stealth

Why so Boxy?

Why so Boxy?
•Reﬂections angle
away from source

Why so Boxy?
away from source
•Also, paint eats
radar waves

Why so Boxy?
away from source
•Also, paint eats
radar waves
•But, hard to ﬂy

Why so Boxy?
away from source
•Also, paint eats
radar waves
•But, hard to ﬂy
•And, crashes a lot

Pay no attention…

Physics of
invisibility

Physics of
invisibility
•Invisibility cloaks

Physics of
invisibility
•Negative refractive indexes

Physics of
invisibility
•Metamaterials

Physics of
invisibility
•Metamaterials
•Optical transformations

Physics of
invisibility
•Metamaterials
•Optical transformations
•General relativity helps make it simple?

Invisibility Cloaks

Invisibility in Practice
“Invisibility is
theoretically possible
captain – the selective
bending of light – but
the power cost is
enormous.
They may have solved
that problem”
– Lt. Cmdr. Spock

Lighten Up!

Lighten Up!
•Slow light

Lighten Up!
•Slow light
•Light that goes faster than light

Lighten Up!
•Slow light
•Stopped light - light that doesn’t go at
all

Lighten Up!
•Slow light
•Stopped light - light that doesn’t go at
all
•Backwards light

Cat’s eyes

Fermat’s
principle
Direct but slow
Faster

Fermat’s
principle
Direct but slow
Faster
Fastest!

Simple Lens

Lüneberg Lens

Positive
Refraction

Negative Refraction

http://www.loa.espci.fr/cargese2009/Cargese2009_Pendry.pdfInvisibility: Theory & Practice - FOSSCON, Aug 10th 2013
Time Reversal

Negative cancels
positive

Super lens

Warping space

Like water
around a rock…

Hiding a lump
under the carpet

Invisible Tanks

Foreseeable
Civilian
Uses …

•Trafﬁc light visibility
Foreseeable
Civilian
Uses …

•Earthquake &
tsunami avoidance
Foreseeable
Civilian
Uses …

•Earthquake &
tsunami avoidance
•Locating reactor core
with muons
Foreseeable
Civilian
Uses …

•Earthquake &
tsunami avoidance
•Locating reactor core
with muons
•Tourist revenue
enhancement…
Foreseeable
Civilian
Uses …

Black holes in
the laboratory

Black holes as
lenses
Einstein Rings

Time Cloak

How to Vanish a Cat

How to Vanish a Cat
The apparatus uses the fact that the
human eye can’t see phase information
to help route light around the “space
between”. With no need to preserve
the phase, the design is much simpler!
Only works from a few directions, alas.
http://arxiv.org/abs/1306.1780

Seeing the
invisible

Seeing the
invisible
•It’s all about the math
(really the information!)

Seeing the
invisible
•Brains at play

Seeing the
invisible
•Brains at play
•Any sufﬁciently
advanced science will
look like magic

Be Seeing You

Be Seeing You
•Forbes - Dazzled & Deceived - 2009 [Fun]

Be Seeing You
•Perkowitz - Slow Light: Invisibility,
Teleportation, & Other Mysteries of Light -
2011 [Solid]

Be Seeing You
2011 [Solid]
•Beech - Physics of Invisibility: A Story of Light
& Deception - 2011 [Lots of pictures]

Be Seeing You
2011 [Solid]
•Beech - Physics of Invisibility: A Story of Light
& Deception - 2011 [Lots of pictures]
•Leonhardt - Geometry & Light: Science of
Invisibility - 2010 [Brain-Frier]

Invisibility: Theory and Practice - v2

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