Talk:Squeezed coherent state

message: "The most general wave function that satisfies the identity above" WHICH "identity above"? It's not clear  — Preceding unsigned comment added by 31.131.246.13 (talk) 07:07, 17 September 2018 (UTC)

message: Where is r defined? Maybe I'm just not seeing it. Sigfpe (talk) 05:12, 26 July 2015 (UTC)
thread_title: Variable r in Operator representation of squeezed coherent states

message: I believe that a squeezed state refers to any state where the uncertainty in one quadrature of two non-commuting operators is less than the standard quantum limit. I.e., if 
[A,B]=C
then
\Delta A \Delta B \ge C/2.
In that case, the standard quantum limit is
SQL = \sqrt{C/2}.
If the uncertainty in A is less than the standard quantum limit, then we say that the state is squeezed with respect to A.  —Preceding unsigned comment added by 24.7.65.235 (talk) 02:28, 22 April 2008 (UTC)
replies: text: Agreed, generally squeezed states refer to some state at the minimum bound of the HUP where one observable gets a smaller share of the uncertainty at the expense of the other.  There is certainly a problem with the whole premise of the start of this article.  The text is actually talking about a minimum uncertainty state (which all coherent and vacuum states of the harmonic oscillator satisfy).  Its only `squeezed' when the uncertainties are no longer equal. In responce to the comment above, one has to be careful with the term standard quantum limit as it means different things to different people. Fincle (talk) 00:19, 17 June 2015 (UTC)
thread_title:  Wrong definition? 

message: Reference 7 is behind a restricted access server.
Please delete reference 7 and provide a reference to a published account of the same or similar work.  — Preceding unsigned comment added by 130.68.20.187 (talk) 15:01, 12 September 2011 (UTC)
thread_title:  Bad Reference 7 

message: The definition section does not define the terms used in the example section that follows immediately afterwards. So, 
* What is amplitude-squeezed, phase-squeezed or quadrature-squeezed?
* What is a 'squeezed vacuum'? Calling it an 'absense of excitation' keeps it completely mysterious.
* What does noise have to do with coherent states? Why is it quantum noise and not some other noise?  (or rather, how do we know its quantum noise, and not something else?) How does one write down the equations for noise? Normally, noise is some stochastic process, or, from measure theory, related to some measure over some space; what's the process? what's the measure space?
* Noise suggests we are working with a mixed states, not a pure states .. !? right??  Yet the standard definitions of coherenet states give eqns for pure states. So ...?
* The squeezed state is prepared as the eigenstate of some operator, as defined in the definition section. Fine. But the measurements are made using some other observables ... which ones? What   basis are the written in?
Inquiring minds want to know. User:Linas (talk) 00:06, 1 December 2013 (UTC)
replies: text: Agreed, the article is not really complete. 178.39.122.125 (talk) 06:14, 1 September 2016 (UTC)
thread_title:  Unclear 

message: Why does the Negative Energy article link to this one?  It seems that the article mentions uncertainty in one quadrature component (of the Heisenberg uncertainty principle) being traded off with another in some way.  Does this ever result in negative energy when dealing with certain waveforms?  Would any experimental setup ever allow negative energy to be 'produced' in more appreciable quantities?  
ASavantDude (talk) 23:56, 19 July 2015 (UTC)
thread_title: Negative Energy Link

message: Is a squeezed coherent state coherent? Sometimes the article says it is, sometimes it says the contradiction. All in all it makes little sense. 178.39.122.125 (talk) 06:13, 1 September 2016 (UTC)
thread_title:  Is a squeezed coherent state coherent? 

message: In the introduction we read "Note that a squeezed state does not need to saturate the uncertainty principle.", while in the Operator section we read "Therefore, a squeezed coherent state saturates the Heisenberg Uncertainty Principle ... with reduced uncertainty in one of its quadrature components and increased uncertainty in the other.
What is correct here?  — Preceding unsigned comment added by 193.83.106.80 (talk) 17:19, 22 March 2018 (UTC)
thread_title:  Saturate or not? 

message: I looked at this article, and found it mostly incomprehensible. Then I looked at this IOP science page ( https://iopscience.iop.org/article/10.1088/1464-4266/7/5/B01 ), which starts with
By only requiring the reader to know the Heisenberg Heisenberg Uncertainty Principle (which is pretty common knowledge, and it doesn't even REALLY require the reader to understand that), this single sentence is able to explain more to a relative layman like me than this entire Wikipedia article as it currently stands. (That might be an exaggeration. The third paragraph of this article explains this pretty well. It's just messy in how it says it and weirdly far down, and it made me feel like that might be tangential to the page's main point and there was something more important I wasn't understanding.) It also gives the background as to what the basic idea this article is even supposed to be talking about is, to help such readers figure out what the specifics are trying to say and what is and isn't important to whyever they looked this up. I hesitated to edit the beginning of this article because I wasn't certain that I actually understood, and didn't want to mess up any important nuance in the beginning of the article, particularly with regards to the "coherent" part, since I'm not sure if there's such a thing as an "squeezed incoherent state", and with regards to the number of dimensions, since I'm not sure if a "coherent state" necessarily considers both of the variables needed to make the "squeezing" necessary, though I would think that it would, since those are variables that are necessarily related by the Heisenberg Uncertainty Principle. I will suggest a change though. Currently, the beginning of the article looks like this:
I would suggest SOMETHING like this:
 DubleH (talk) 08:39, 13 August 2022 (UTC)
replies: text: Looking at the page on squeezed states of light has confirmed my fear of not knowing exactly what I'm talking about and my choice to not edit the article myself. I assumed that a "squeezed coherent state" was a subtype of a "coherent state", but that article says that "light is in a squeezed state if its electric field strength Ԑ for some phases \vartheta has a quantum uncertainty smaller than that of a coherent state" and "must also have phases at which the electric field uncertainty is anti-squeezed, i.e. larger than that of a coherent state." This implies that a squeezed coherent state is actually NOT a coherent state at all, but rather a state that is squeezed relative to a "coherent state". Alternatively, maybe a "squeezed coherent state" IS a coherent state, and the article on squeezed states of light just meant that such a state must be squeezed relative to some OTHER coherent state in order for it to be meaningfully called "squeezed". I honestly couldn't tell you yet. DubleH (talk) 08:58, 13 August 2022 (UTC)
thread_title:  Basic definition of why it's "squeezed" before getting into the math?