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| Don Stauffer... |
 Posted: Sat Oct 10, 2009 8:34 am |
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Guest
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I was reading a brief news note in an electronics magazine about a Yale
group that developed a "mechanical" switch on a chip using light.
There were two waveguides placed very close together on the chip, and if
they ran light through them in phase, the two waveguides had an
attractive force. If they delayed light in one by quarter wavelength
there was a repulsion.
I thought optical waveguides were very efficient, in which case there
would be little field outside of waveguide. Or, is this evanescent
propogation (the article did not say exactly how close the two
waveguides wer?. |
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| Hazem... |
| Posted: Sat Oct 10, 2009 8:34 am |
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Guest
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On Oct 10, 10:34 am, Don Stauffer <stauf... at (no spam) usfamily.net> wrote:
[quote:d8edf0b8ea]I was reading a brief news note in an electronics magazine about a Yale
group that developed a "mechanical" switch on a chip using light.
There were two waveguides placed very close together on the chip, and if
they ran light through them in phase, the two waveguides had an
attractive force. If they delayed light in one by quarter wavelength
there was a repulsion.
I thought optical waveguides were very efficient, in which case there
would be little field outside of waveguide. Or, is this evanescent
propogation (the article did not say exactly how close the two
waveguides wer?.
[/quote:d8edf0b8ea]
Nature does not allow discontinuities. Therefore, as a matter of
physical law (or maybe something more fundamental!) the optical field
cannot suddenly drop from a finite value inside the waveguide to zero
at the waveguide boundary. Thus, we have evanescent fields outside the
waveguide. The key is that evanescent fields are non-radiating, unless
allowed to couple to something (like another waveguide) in the
vicinity.
This principle of no discontinuities is general and has far-reaching
implications. From this point of view, it's easy to see why we have
phenomena like the one described in the paper you mentioned.
One of the interesting thought experiments i entertain myself with is:
If nature has no discontinuities, then every particle must be infinite
in extent. If so, can you send a signal through a single particle to a
distant location by perturbing it locally? What is the speed of
transmission? does this have anything to do with non-locality? Can't
particles be understood as perturbations themselves in some
fundamental field?
Regards,
Hazem |
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| Salmon Egg... |
| Posted: Sat Oct 10, 2009 10:06 am |
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Guest
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In article <4ad09b62$0$89384$815e3792 at (no spam) news.qwest.net>,
Don Stauffer <stauffer at (no spam) usfamily.net> wrote:
[quote:84b68ff0e8]I was reading a brief news note in an electronics magazine about a Yale
group that developed a "mechanical" switch on a chip using light.
There were two waveguides placed very close together on the chip, and if
they ran light through them in phase, the two waveguides had an
attractive force. If they delayed light in one by quarter wavelength
there was a repulsion.
I thought optical waveguides were very efficient, in which case there
would be little field outside of waveguide. Or, is this evanescent
propogation (the article did not say exactly how close the two
waveguides wer?.
[/quote:84b68ff0e8]
Optical waveguides can be understood in various ways. One way is in
terms of total internal reflection (TIR). TIR is most easily pictured in
terms of flat surfaces, but it is true in circular geometry as well.
Clad fibers propagate in modes that do not allow ray penetration into
the cladding because the idex there is too low. That is TIR. There are
evanescent fields in the cladding. Usually, the cladding is sufficiently
thick to prevent any significant field leakage through the cladding. The
cladding can be made thin or polished away to increase the coupling to
the outside world.
Bill
--
Private Profit; Public Poop! Avoid collateral windfall! |
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| Hazem... |
| Posted: Sat Oct 10, 2009 12:56 pm |
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Guest
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On Oct 10, 6:14 pm, Salmon Egg <Salmon... at (no spam) sbcglobal.net> wrote:
[quote:e14e02b257]In article
41baee38-9280-4c8d-8739-543286a14... at (no spam) e8g2000yqo.googlegroups.com>,
Hazem <hazem.biqa... at (no spam) gmail.com> wrote:
Nature does not allow discontinuities. Therefore, as a matter of
physical law (or maybe something more fundamental!) the optical field
cannot suddenly drop from a finite value inside the waveguide to zero
at the waveguide boundary. Thus, we have evanescent fields outside the
waveguide. The key is that evanescent fields are non-radiating, unless
allowed to couple to something (like another waveguide) in the
vicinity.
Where is this written? What does it mean? Is it a fundamental law? Is it
derived? Is it deduced? How is it used to predict anything?
Bill
--
Private Profit; Public Poop! Avoid collateral windfall!
[/quote:e14e02b257]
Consider the alternative, that discontinuities are allowed, even
sometimes. That would lead to a whole lot of nonsensical results that
we know do not in fact occur.
Show me one example of a true discontinuity in nature. I just showed
you how non-discontinuity predicts evanescent fields.
Hazem |
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| Salmon Egg... |
| Posted: Sat Oct 10, 2009 4:14 pm |
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Guest
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In article
<41baee38-9280-4c8d-8739-543286a14919 at (no spam) e8g2000yqo.googlegroups.com>,
Hazem <hazem.biqaeen at (no spam) gmail.com> wrote:
[quote:7f785e14c5]Nature does not allow discontinuities. Therefore, as a matter of
physical law (or maybe something more fundamental!) the optical field
cannot suddenly drop from a finite value inside the waveguide to zero
at the waveguide boundary. Thus, we have evanescent fields outside the
waveguide. The key is that evanescent fields are non-radiating, unless
allowed to couple to something (like another waveguide) in the
vicinity.
[/quote:7f785e14c5]
Where is this written? What does it mean? Is it a fundamental law? Is it
derived? Is it deduced? How is it used to predict anything?
Bill
--
Private Profit; Public Poop! Avoid collateral windfall! |
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| Phil Hobbs... |
| Posted: Sat Oct 10, 2009 8:24 pm |
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Guest
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Hazem wrote:
[quote:42c13b1c1a]On Oct 10, 6:14 pm, Salmon Egg <Salmon... at (no spam) sbcglobal.net> wrote:
In article
41baee38-9280-4c8d-8739-543286a14... at (no spam) e8g2000yqo.googlegroups.com>,
Hazem <hazem.biqa... at (no spam) gmail.com> wrote:
Nature does not allow discontinuities. Therefore, as a matter of
physical law (or maybe something more fundamental!) the optical field
cannot suddenly drop from a finite value inside the waveguide to zero
at the waveguide boundary. Thus, we have evanescent fields outside the
waveguide. The key is that evanescent fields are non-radiating, unless
allowed to couple to something (like another waveguide) in the
vicinity.
Where is this written? What does it mean? Is it a fundamental law? Is it
derived? Is it deduced? How is it used to predict anything?
Bill
--
Private Profit; Public Poop! Avoid collateral windfall!
Consider the alternative, that discontinuities are allowed, even
sometimes. That would lead to a whole lot of nonsensical results that
we know do not in fact occur.
Show me one example of a true discontinuity in nature. I just showed
you how non-discontinuity predicts evanescent fields.
Hazem
[/quote:42c13b1c1a]
There aren't discontinuities in the values of physical observables as
functions of space and time, but there are in other situations, e.g.
elongation as a function of stress in a bar.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net |
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| Helpful person |
| Posted: Sun Oct 11, 2009 4:22 am |
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Joined: 22 Jun 2004
Posts: 839
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On Oct 10, 10:24 pm, Phil Hobbs
<pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
[quote:cef06fd5f4]Hazem wrote:
On Oct 10, 6:14 pm, Salmon Egg <Salmon... at (no spam) sbcglobal.net> wrote:
In article
41baee38-9280-4c8d-8739-543286a14... at (no spam) e8g2000yqo.googlegroups.com>,
Hazem <hazem.biqa... at (no spam) gmail.com> wrote:
Nature does not allow discontinuities. Therefore, as a matter of
physical law (or maybe something more fundamental!) the optical field
cannot suddenly drop from a finite value inside the waveguide to zero
at the waveguide boundary. Thus, we have evanescent fields outside the
waveguide. The key is that evanescent fields are non-radiating, unless
allowed to couple to something (like another waveguide) in the
vicinity.
Where is this written? What does it mean? Is it a fundamental law? Is it
derived? Is it deduced? How is it used to predict anything?
Bill
--
Private Profit; Public Poop! Avoid collateral windfall!
Consider the alternative, that discontinuities are allowed, even
sometimes. That would lead to a whole lot of nonsensical results that
we know do not in fact occur.
Show me one example of a true discontinuity in nature. I just showed
you how non-discontinuity predicts evanescent fields.
Hazem
There aren't discontinuities in the values of physical observables as
functions of space and time, but there are in other situations, e.g.
elongation as a function of stress in a bar.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot nethttp://electrooptical.net- Hide quoted text -
- Show quoted text -
[/quote:cef06fd5f4]
I believe (maybe) that one can have discontinuities in higher order
diffentials, although Hazem's point is well taken.
Where is the discontinuity for elongation as a function of stress in a
bar? Are you refering to the plastic region?
www.richardfisher.com |
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| Don Stauffer... |
| Posted: Sun Oct 11, 2009 10:17 am |
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Guest
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Hazem wrote:
[quote:46b4b2295c]
One of the interesting thought experiments i entertain myself with is:
If nature has no discontinuities, then every particle must be infinite
in extent. If so, can you send a signal through a single particle to a
distant location by perturbing it locally? What is the speed of
transmission? does this have anything to do with non-locality? Can't
particles be understood as perturbations themselves in some
fundamental field?
Regards,
Hazem
So are you saying that the force IS from the evanescent field?[/quote:46b4b2295c] |
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| Phil Hobbs... |
| Posted: Sun Oct 11, 2009 1:00 pm |
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Guest
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Helpful person wrote:
[quote:f04e0e8f2c]On Oct 10, 10:24 pm, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Hazem wrote:
On Oct 10, 6:14 pm, Salmon Egg <Salmon... at (no spam) sbcglobal.net> wrote:
In article
41baee38-9280-4c8d-8739-543286a14... at (no spam) e8g2000yqo.googlegroups.com>,
Hazem <hazem.biqa... at (no spam) gmail.com> wrote:
Nature does not allow discontinuities. Therefore, as a matter of
physical law (or maybe something more fundamental!) the optical field
cannot suddenly drop from a finite value inside the waveguide to zero
at the waveguide boundary. Thus, we have evanescent fields outside the
waveguide. The key is that evanescent fields are non-radiating, unless
allowed to couple to something (like another waveguide) in the
vicinity.
Where is this written? What does it mean? Is it a fundamental law? Is it
derived? Is it deduced? How is it used to predict anything?
Bill
--
Private Profit; Public Poop! Avoid collateral windfall!
Consider the alternative, that discontinuities are allowed, even
sometimes. That would lead to a whole lot of nonsensical results that
we know do not in fact occur.
Show me one example of a true discontinuity in nature. I just showed
you how non-discontinuity predicts evanescent fields.
Hazem
There aren't discontinuities in the values of physical observables as
functions of space and time, but there are in other situations, e.g.
elongation as a function of stress in a bar.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot nethttp://electrooptical.net- Hide quoted text -
- Show quoted text -
I believe (maybe) that one can have discontinuities in higher order
diffentials, although Hazem's point is well taken.
Where is the discontinuity for elongation as a function of stress in a
bar? Are you refering to the plastic region?
www.richardfisher.com
[/quote:f04e0e8f2c]
No, I'm talking about the elongation going to infinity when the bar
fails. (If anyone is going to be pedantic about infinity, say the bar
is a long skinny one attached to Pioneer 10.)
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net |
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| Timo Nieminen... |
| Posted: Sun Oct 11, 2009 4:58 pm |
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Guest
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On Sat, 10 Oct 2009, Don Stauffer wrote:
[quote:2a9e3475af]I was reading a brief news note in an electronics magazine about a Yale
group that developed a "mechanical" switch on a chip using light.
There were two waveguides placed very close together on the chip, and if
they ran light through them in phase, the two waveguides had an
attractive force. If they delayed light in one by quarter wavelength
there was a repulsion.
I thought optical waveguides were very efficient, in which case there
would be little field outside of waveguide. Or, is this evanescent
propogation (the article did not say exactly how close the two
waveguides wer?.
[/quote:2a9e3475af]
In a single-mode dielectric waveguide, most of the energy is in the
evanescent field. Most of this will be in the cladding, so it's a matter
of terminology whether or not there is little field outside the waveguide.
In a weakly-guiding waveguide (like most dielectric waveguides), the
evanescent field only fall off slowly (thus the problems with
miniaturisation of photonics due to evanescent coupling and bending
losses).
The forces above are due to the evanescent fields. The "very close
together" might be on the order of a wavelength or few.
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://espace.uq.edu.au/list/author_id/1189/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html |
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| Helpful person |
| Posted: Mon Oct 12, 2009 1:27 am |
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Joined: 22 Jun 2004
Posts: 839
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On Oct 11, 3:00 pm, Phil Hobbs
<pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
[quote:1daff73fed]Helpful person wrote:
On Oct 10, 10:24 pm, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Hazem wrote:
On Oct 10, 6:14 pm, Salmon Egg <Salmon... at (no spam) sbcglobal.net> wrote:
In article
41baee38-9280-4c8d-8739-543286a14... at (no spam) e8g2000yqo.googlegroups.com>,
Hazem <hazem.biqa... at (no spam) gmail.com> wrote:
Nature does not allow discontinuities. Therefore, as a matter of
physical law (or maybe something more fundamental!) the optical field
cannot suddenly drop from a finite value inside the waveguide to zero
at the waveguide boundary. Thus, we have evanescent fields outside the
waveguide. The key is that evanescent fields are non-radiating, unless
allowed to couple to something (like another waveguide) in the
vicinity.
Where is this written? What does it mean? Is it a fundamental law? Is it
derived? Is it deduced? How is it used to predict anything?
Bill
--
Private Profit; Public Poop! Avoid collateral windfall!
Consider the alternative, that discontinuities are allowed, even
sometimes. That would lead to a whole lot of nonsensical results that
we know do not in fact occur.
Show me one example of a true discontinuity in nature. I just showed
you how non-discontinuity predicts evanescent fields.
Hazem
There aren't discontinuities in the values of physical observables as
functions of space and time, but there are in other situations, e.g.
elongation as a function of stress in a bar.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot nethttp://electrooptical.net-Hide quoted text -
- Show quoted text -
I believe (maybe) that one can have discontinuities in higher order
differentials, although Hazem's point is well taken.
Where is the discontinuity for elongation as a function of stress in a
bar? Are you refering to the plastic region?
www.richardfisher.com
No, I'm talking about the elongation going to infinity when the bar
fails. (If anyone is going to be pedantic about infinity, say the bar
is a long skinny one attached to Pioneer 10.)
Cheers
Phil Hobbs
[/quote:1daff73fed]
I'm not sure that at the molecular or quantum level that is a true
discontinuity.
www.richardfisher.com |
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| Phil Hobbs... |
| Posted: Mon Oct 12, 2009 8:35 am |
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Guest
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Helpful person wrote:
[quote:023772196a]On Oct 11, 3:00 pm, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Helpful person wrote:
On Oct 10, 10:24 pm, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Hazem wrote:
On Oct 10, 6:14 pm, Salmon Egg <Salmon... at (no spam) sbcglobal.net> wrote:
In article
41baee38-9280-4c8d-8739-543286a14... at (no spam) e8g2000yqo.googlegroups.com>,
Hazem <hazem.biqa... at (no spam) gmail.com> wrote:
Nature does not allow discontinuities. Therefore, as a matter of
physical law (or maybe something more fundamental!) the optical field
cannot suddenly drop from a finite value inside the waveguide to zero
at the waveguide boundary. Thus, we have evanescent fields outside the
waveguide. The key is that evanescent fields are non-radiating, unless
allowed to couple to something (like another waveguide) in the
vicinity.
Where is this written? What does it mean? Is it a fundamental law? Is it
derived? Is it deduced? How is it used to predict anything?
Bill
--
Private Profit; Public Poop! Avoid collateral windfall!
Consider the alternative, that discontinuities are allowed, even
sometimes. That would lead to a whole lot of nonsensical results that
we know do not in fact occur.
Show me one example of a true discontinuity in nature. I just showed
you how non-discontinuity predicts evanescent fields.
Hazem
There aren't discontinuities in the values of physical observables as
functions of space and time, but there are in other situations, e.g.
elongation as a function of stress in a bar.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot nethttp://electrooptical.net-Hide quoted text -
- Show quoted text -
I believe (maybe) that one can have discontinuities in higher order
differentials, although Hazem's point is well taken.
Where is the discontinuity for elongation as a function of stress in a
bar? Are you refering to the plastic region?
www.richardfisher.com
No, I'm talking about the elongation going to infinity when the bar
fails. (If anyone is going to be pedantic about infinity, say the bar
is a long skinny one attached to Pioneer 10.)
Cheers
Phil Hobbs
I'm not sure that at the molecular or quantum level that is a true
discontinuity.
www.richardfisher.com
[/quote:023772196a]
In what way is delta L going off to infinity not a discontinuity? Atoms
or no atoms? Note that I was clear that observable _functions of time
and space_ are all continuous, but not _all_ physical functions.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net |
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| Helpful person |
| Posted: Mon Oct 12, 2009 9:41 am |
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Joined: 22 Jun 2004
Posts: 839
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On Oct 12, 10:35 am, Phil Hobbs
<pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
[quote:a255d19e66]Helpful person wrote:
I'm not sure that at the molecular or quantum level that is a true
discontinuity.
www.richardfisher.com
In what way is delta L going off to infinity not a discontinuity? Atoms
or no atoms? Note that I was clear that observable _functions of time
and space_ are all continuous, but not _all_ physical functions.
Cheers
Phil Hobbs
How do you define a physical function?[/quote:a255d19e66]
www.richardfisher.com |
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| Phil Hobbs... |
| Posted: Mon Oct 12, 2009 3:31 pm |
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Guest
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Helpful person wrote:
[quote:c60e4cfb19]On Oct 12, 10:35 am, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Helpful person wrote:
I'm not sure that at the molecular or quantum level that is a true
discontinuity.
www.richardfisher.com
In what way is delta L going off to infinity not a discontinuity? Atoms
or no atoms? Note that I was clear that observable _functions of time
and space_ are all continuous, but not _all_ physical functions.
Cheers
Phil Hobbs
How do you define a physical function?
www.richardfisher.com
[/quote:c60e4cfb19]
A function referring to some physical observable. Such as the
separation between two points on a steel bar.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net |
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| Helpful person |
| Posted: Tue Oct 13, 2009 1:22 am |
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Joined: 22 Jun 2004
Posts: 839
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On Oct 12, 5:31 pm, Phil Hobbs
<pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
[quote:1b96c28ce9]Helpful person wrote:
On Oct 12, 10:35 am, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Helpful person wrote:
I'm not sure that at the molecular or quantum level that is a true
discontinuity.
www.richardfisher.com
In what way is delta L going off to infinity not a discontinuity? Atoms
or no atoms? Note that I was clear that observable _functions of time
and space_ are all continuous, but not _all_ physical functions.
Cheers
Phil Hobbs
How do you define a physical function?
www.richardfisher.com
A function referring to some physical observable. Such as the
separation between two points on a steel bar.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot nethttp://electrooptical.net- Hide quoted text -
- Show quoted text -
[/quote:1b96c28ce9]
OK
www.richardfisher.com |
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