Talk:Cavity optomechanics

Missing sections

• History of the field including radiation pressure (Maxwell) and the fathers of the field: Braginski, Tombesi, Jacobs, Knight and Bowmester.
• Applications: Quantum memory, force sensors and gravitational wave detectors
• Neighbouring fields: BEC, Ion traps

--Schmoele (talk) 15:38, 29 December 2011 (UTC)

GOCE copyedit request

I will also call upon any other experts watching this article, as there is a lot to cover. I have a rudimentary understanding of physics from university so please bear with me, especially if I have questions about how equations work. Because there's a lot of jargon that remains undefined, I will be colouring those red. My questions will still be in order going down the article.

• The name of the field relates to the main effect of interest: the enhancement of radiation pressure interaction between light (photons) and matter using optical resonators (cavities). Links preserved. Is there a reason why "optical resonators (cavities)" is used and not "optical cavity"? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Furthermore, one may envision optomechanical structures to allow the realization of Schrödinger's cat. Why is this important? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Macroscopic objects consisting of billions of atoms share collective degrees of freedom which may behave quantum mechanically, e.g. a sphere of micrometer diameter being in a spatial superposition between two different places. Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Optomechanical structures provide new methods to test the predictions of quantum mechanics and decoherence models and thereby might allow to answer some of the most fundamental questions in modern physics. What fundamental questions are answered? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• There is always elastic light scattering, with the outgoing light frequency identical to the incoming frequency $\omega '=\omega$. Both these terms need to be described. What do each of these define? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The vibrations gain or lose energy, respectively [...] What are the situations where vibrations gain or lose energy? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• [...] for these Stokes/anti-Stokes processes, while optical sidebands are created around the incoming light frequency [...] Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The purpose of the cavity is to select optical frequencies (e.g. to suppress the Stokes process) that resonantly enhance the light intensity and to enhance the sensitivity to the mechanical vibrations. The sensitivity of what? Optical frequencies? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• One possible way to do this is by using optical cavities. If a photon is enclosed between two mirrors, where one is the oscillator and the other is a heavy fixed one [...] A "heavy fixed" what? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The number of times a photon can transfer its momentum is directly related to the finesse of the cavity [...] Link preserved, undefined jargon. "Finesse" is not helpfully defined in the wikilinked article. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Another advantage of optical cavities is that the modulation of the cavity length through an oscillating mirror can directly be seen in the spectrum of the cavity. Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• and adding it to the intrinsic harmonic oscillator potential of the mechanical oscillator, where $F(x)$ is the slope of the radiation pressure force. Slightly edited. Requesting confirmation that $F(x)$ actually is the slope. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• However, the model is incomplete as it neglects retardation effects due to the finite cavity photon decay rate $\kappa$. Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• For example, assume the equilibrium position sits somewhere on the rising slope of the resonance. Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The consequence of this delayed radiation force during one cycle of oscillation is that work is performed, in this particular case it is negative [...] What does it mean when work is negative? Is mechanical energy absorbed instead of released? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• This can be used to cool down the mechanical motion and is referred to as optical or optomechanical cooling. Does "cooling" slow down mechanical motion? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• It is important for reaching the quantum regime of the mechanical oscillator where thermal noise effects on the device become negligible. Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Heading: Three regimes of operation: cooling, heating, resonance. I'm thinking of this heading being renamed, as there's no association made between heat with the three scenarios below. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• This regime describes "two-mode squeezing". Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• [...] if the growth of the mechanical energy overwhelms the intrinsic losses (mainly mechanical friction). An equation could be helpful here? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• [...] its strength varies with detuning and the laser drive. Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The standard optomechanical setup is a Fabry–Pérot cavity [...] A link to the correct Fabry–Pérot article might be nice. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The optical mode is driven by an external laser. This system can be described by the following effective Hamiltonian [...] Link preserved. I hope that's the right link. There are also some variables in the equation that haven't been defined, like $a^{\dagger }$ and $i$. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• where $P$ is the input power coupled to the optical mode under consideration and $\kappa$ its linewidth. I am assuming that $\kappa$ is the linewidth of the input power? Does this variable have a different definition as opposed to finite cavity photon decay rate? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Expanding the photon number $a^{\dagger }a$, the term $\alpha ^{2}$ can be omitted as it leads to a constant radiation pressure force which simply shifts the resonator's equilibrium position. Slightly edited. I see what looks like the photon number in an earlier equation, but I am confused as to how the number is expanded. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The driving term from the standard Hamiltonian is not part of the linearized Hamiltonian [...] Undefined jargon.
• Here $a_{i}n$ and $b_{i}n$ are the input noise operators (either quantum or thermal noise) and $-\kappa \delta a$ and $-\Gamma \delta p$ are the corresponding dissipative terms. I don't see where $-\Gamma \delta p$ is expanded from in the equations above. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Two main effects of the light on the mechanical oscillator can then be expressed in the following ways: Boldly edited. While the terms are defined elsewhere, it might be friendlier to the reader to remind them what each variable stands for. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The most basic regimes in which the optomechanical system can be operated are defined by the laser detuning and [blank] described above. I think there's a word missing in the spot where I added [blank]. What is it? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The good cavity regime (resolved sideband limit) [...] Undefined jargon, or is it another term to describe "good cavity regime"? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• This requirement leads to a condition for the so-called sideband parameter: $\omega _{m}/\kappa \gg 1$. Just checking, the sideband parameter is ${\frac {\omega _{m}}{\kappa }}$? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• [...] many motional sidebands can be included in the broad cavity linewidth [...] Is this $\kappa$? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• This regime must be distinguished from the (experimentally much more challenging) [...] Nice little tidbit, but is this parenthetical thought really necessary? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• [...] where the bare optomechanical coupling becomes of the order of the cavity linewidth [...] I'm unsure what "becomes" means here. How does it ascend/descend to the "order of the cavity linewidth"? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Heading: Experimental realizations. Maybe we should change this to Experimental applications? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• (although LIGO is dedicated to the detection of gravitational waves and not the investigation of optomechanics specifically). This parenthetical thought seems to be trivial. Is understanding its intended use crucial to understanding cavity optomechanics? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The light is reflected from the mirrors and transfers momentum onto the movable one, which in turn changes the cavity resonance frequency. Link preserved. Is it important that the mirrors be dielectric? I think the qualifier "dielectric" should be in this article explicitly. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Microtoroids that support an optical whispering gallery mode can be either coupled to a mechanical mode of the toroid or evanescently to a nanobeam that is brought in proximity. Emphasis in original, undefined jargon. Does "evanescently" mean "fleeting"? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• [...] or a two-mode scheme is followed where a strong laser is used to drive the optomechanical system into the state of interest and a second laser is used for the read-out of the state of the system. Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Taking spatial superpositions as an example, there might be a size limit to objects which can be brought into superpositions, there might be a limit to the spatial separation of the centers of mass of a superposition or even a limit to the superposition of gravitational fields and its impact on small test masses. The two clauses following "as an example" both look independent; does one rely on the other, or are they actually different concepts that can be separated from one another? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• Some easier to check predictions of quantum mechanics are the prediction of negative Wigner functions for certain quantum states [...] Easier to check than what? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• In addition to the standard cavity optomechanics explained above, there are variations of the simplest model [...] Does "the simplest model" just mean "standard cavity optomechanics"? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• It is useful for creating entanglement and allows backaction-evading measurements. Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• The interaction Hamiltonian would then feature a term $\hbar g_{quad}a^{\dagger }a(b+b^{\dagger })^{2}$ with $g_{sq}={\frac {1}{2}}\left.{\tfrac {d^{2}\omega _{cav}(x)}{dx^{2}}}\right|_{x=0}x_{zpf}^{2}$. Why are these equations important and how do they relate to one another? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)
• [...] coupling several optomechanical systems to each other (e.g. using evanescent coupling [...] Undefined jargon. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)

• These systems share very similar Hamiltonians, but have fewer particles (about 10 for ion traps and $10^{5}$-$10^{8}$ for Bose–Einstein condensates) interacting with the field of light. So ion traps have way fewer particles than Bose–Einstein condensates? Why is LaTeX being used for the Bose–Einstein condensate numbers? Just for the subscript? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)

• It is also related to the field of cavity quantum electrodynamics. Does "it" = "cavity optomechanics"? —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)

Strongly looking forward to answers. —Tenryuu 🐲 ( 💬 • 📝 ) 03:33, 9 September 2020 (UTC)

As no one has responded I will consider this request complete for now. If anyone would like to get this article resolved please ping me. —Tenryuu 🐲 ( 💬 • 📝 ) 16:45, 10 September 2020 (UTC)