Questions tagged [unruh-effect]

This tag is for questions regarding to the Unruh effect (also known as the Fulling–Davies–Unruh effect), the hypothetical prediction that an accelerating observer will observe a thermal bath, like blackbody radiation, whereas an inertial observer would observe none. It was described by Stephen Fulling in 1973, Paul Davies in 1975, and William Unruh in 1976.

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Unruh effect on rotating galaxies?

According to the Unruh effect, an accelerating observer will experience a thermal bath. This is equivalent to Hawking radiation. If we applied this to a spinning galaxy, I wonder if this thermal bath ...
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Can the inertial observer “see” the Unruh accelerated observer's vacuum?

The unruh process is asymmetric. The inertial observer is in his vacuum V0 and the accelerated observer measures $\langle V_0|N|V_0 \rangle$ and sees particles. He is not in his vacuum environment. I ...
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For Hawking radiation, is the scalar field $\phi$ assumed to be in the Unruh vacuum state?

In Hawking's paper "Particle Creation by Black Holes" I'm not really able to pick apart what vacuum state Hawking is assuming the field $\phi$ to be in. The paper "Hawking radiation as ...
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Isn't Unruh effect against the equivalence principle?

Doesn't the Unruh effect violate EP? Since the temperature of an absolutely accelerating reference frame would be different from an inertial one according to this effect, then one finds a criterion to ...
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Unruh particles

When we accelerate, an event horizon forms behind us resulting in Unruh radiation. In this kind of scenario, the existence of the radiation particles themselves is observer dependent. My question is: ...
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How to relate the coordinates of a lab-frame observer and an uniformly accelerating observer?

If there is lab-frame observer with coordinates $(t,x)$ and a uniformly acceletaing observer in $1+1$ dimensional flat Minkowski spacetime with coordinates $(t',x')$, can we analytically relate $(t',...
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Is the Unruh effect a special relativistic effect or a general relativistic effect?

If an observer moves in an accelerated frame in flat spacetime, the vacuum looks like a thermal distribution of particles to that observer. This is the Unruh effect. Is it a special relativistic (SR) ...
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Why a mode on Minkowsky SpaceTime becomes two modes on Rindler Spacetime

----I am a student on Quantum Computing--- For the whole undertanding of "Tetrapartite entanglement measures of GHZ state with uniform acceleration" by Qiang Dong. https://doi.org/10.1088/...
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How does the Unruh effect create particles?

I've read that the Rindler horizon cuts off access to fundamental quantum fields and leads to a mixing of positive and negative frequencies via the Bogoliubov transformations. But here is where I have ...
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Can Unruh particles be blocked on their way from the horizon?

Can you shield yourself from Unruh particles? In an old answer to a different question, Ron Maimon says yes: You should think of the radiation as coming from the horizon--- if you place a ...
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Direction of Unruh radiation

In case of a black hole, the direction of the Hawking radiation is from the horizon to the observer. The corresponding effect in the Rindler spacetime is the Unruh radiation. Intuitively, a rapidly ...
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Does an object falling into a black-hole get destoyed by Unruh radiation?

My basic understanding of the Unruh effect is that an accelerating observer will experience black-body radiation proportional to the magnitude of the local acceleration, while an observer in an ...
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Why does annihilation and creation operator mix in curved spacetime?

When doing QFT in curved spacetime we do Bogoliubov transformation to find one set of annihilation and creation operators in terms of others. In the paper Particle creation by black holes Hawking ...
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Firewall paradox and causal horizons

What in the blackhole firewall paradox even requires a black hole? That is, wouldn't the argument also apply to a Rindler horizon, or any other causal horizon? I thought one of the lessons of Unruh ...
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Rindler horizons as limits

Consider a worldline $\bf{W}$ that accelerates at constant rate $\alpha$ only between $-t_0$ and $t_0$, and is otherwise inertial before $-t_0$ and after $t_0$. For all finite $t_0$ there is no ...
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Does Hawking radiation lead to black hole evaporation / reduction of black hole mass?

As I understand, Hawking radiation leads to black hole evaporation, resp. a black hole would lose mass due to that effect. Now Hawking radiation is very similar to Unruh radiation, i.e. some (apparent)...
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Unruh effect for finite period of low acceleration

I am trying to find out about the Unruh effect in the case of a finite period of low acceleration. I understand the following: The calculation leading to a thermal spectrum at the Unruh temperature ...
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What is the experimental evidence - direct or indirect - for Hawking or Unruh radiation?

I'm wondering what evidence exists, direct or indirect, for Hawking or Unruh radiation. I believe one of the initial goals for the Fermi LAT mission was to look for evaporating microscopic black ...
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Ways to derive black-body radiation in Unruh effect

I know two ways to derive black-body radiation in Unruh effect and they are: Using Bogoliubov coefficients (N. D. Birrell and Paul Davies) Using Page approximation (David J. Toms and Leonard Parker) ...
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On the necessity of an event horizon for the Hawking-Unruh effect

I first explain my reasoning. I know that a Schwarzschild metric is the right metric outside any spherical object, but I also know that it is correct in the empty space. So I thought: why we don't ...
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Hawking radiation and Unruh effect

I recently read about the Hawking effect and I noticed that formally, in its general lines, the derivation is very similar to that of the Unruh eff. In the latter case we write the Fock states in a ...
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Is there somesort of “recipe” to check if an spacetime exibit the Unruh effect?

Firstly I don't know for sure if this question makes a solid sense, concerning the physical phenomena. I) Unruh Effect Now, we have then the Unruh effect which appears just by considering the ...
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Minkowski space and Rindler spaces, What's relation?

To describe the dynamic of a qubit one can use the Minkowski cordinates, But when that qubit is accelerated with Unruh acceleration we need Rindler cordinate . So, what is UNRUH acceleration? and ...
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Are Bremsstrahlung and the Unruh effect equivalent?

This paper argues that the absorption and emission rates from and to the thermal Unruh bath of a proton viewed in a coaccelerated frame is equal to the emission rated viewed from an inertial observer. ...
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What are zero-energy Rindler photons?

In the discussion of the Unruh effect and Bremsstrahlung (e.g. here) I always come across "zero-energy Rindler photons". What exactly are these? Shouldn't a zero-energy photon correspond to a static ...
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Why to we take the Minkowski vacuum to calculate the thermal Unruh distribution?

Looking at a derivation for the Unruh effect, this generally ends with a calculation of the particle distrubution: $$\langle{0_M}|b^\dagger b|0_M\rangle=\frac{1}{e^{\hbar\omega/k_BT_U}-1}$$ where $b$ ...
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Do Rindler horizons evaporate?

It is thought that black holes radiate via Hawking radiation and consequently evaporate. Rindler horizons too emit radiation. Are they also thought to undergo a similar process of evaporation?
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Question about path integral step of the rindler decomposition

In most papers where I've read about Rindler decomposition and the Unruh effect ( see for example [1] or [2]) they start by saying that they want to find the wavefunction of the vacuum state in the ...
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Does thermal state in Rindler spacetime correspond to Minkowski vacuum?

We know that the Minkowski vacuum corresponds to the thermal state in a Rindler wedge at Unruh temp. But does the thermal state in one Rindler wedge at Unruh temperature uniquely map to the Minkowski ...
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Rindler-Fulling Quantization - Rindler mode expansion of $\phi$: why are we ignoring the Past and Future Wedges?

I am following along Chapter 2 of Takagi's Vacuum noise and stress induced by uniform accelerator. I am at the point of performing the Rindler-Fulling Quantization of a real scalar field, where you ...
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Can an Observer Distinguish between Unruh Effect and Hawking Radiation by Measuring Temperature?

In Unruh effect, the temperature of background appears to be proportional to acceleration. On the other hand, the temperature of a black hole is inversely proportional to its mass. If the two ...
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Big Rip: will cosmic event horizon's Unruh radiation balance accelerating expansion?

The way I've seen the expansion of the universe described, it seems to work a bit like an inside-out black hole: an event horizon beyond which there is no causal connection, light from beyond it can't ...
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What conceivable connection is there between the cosmological constant and radius of the Universe?

You probably noticed that the radius of the (observable) Universe in Planck lengths $R$ (about $10^{60}$) and the cosmological constant $\Lambda$ (about $10^{-120}$) in natural units obey ...
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Why doesn't an observer at rest on the Earth see Unruh radiation? [duplicate]

It is well know that QFT predicts that an accelerated observer would see Unruh radiation. This is related to the presence of a Rindler horizon and leads to the conclusion that an inertial and an ...
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Is there a satisfactory resolution to the Rotating Detector Puzzle?

The Rotating Detector Puzzle refers to the dilemma when trying to study how a rotating detector interacts with the background vacuum. The trail of literature that I found are these papers: p1, p2, p3, ...
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What is the effect of the locality condition if a „Rindler observer“ hovers close to a black hole?

Consider a „Rindler observer“ hovering close to the event horizon of a black hole, whereby flat spacetime is assumed locally. Does this observer see the same Unruh radiation like a Rindler observer ...
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Why does the Unruh effect not cause a physical contradiction?

If the Unruh effect says that the temperature of space depends on one's acceleration, such that an accelerating observer will observe that hir vacuum consists of a thermal bath at some elevated ...
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Hawking Radiation of normal gravitational field

If the event horizon of a black hole can radiate, then is it possible that normal gravitational field also radiates? The radiation will probably be very low, but still there could be some. Also by ...
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Schwinger effect verified by Unruh temperature?

According to https://arxiv.org/abs/1407.4569, equation.(2.15), the Schwinger electron-positron pair production rate in Minkowski space, $N_S$, is given in natural units by $$N_S\sim\exp(-\frac{m}{2T_U}...
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Electromagnetic Unruh/Hawking effect? (Improved argument) [closed]

This is an improved version of the argument in Electromagnetic Unruh effect? In the quantum vacuum particle pairs, with total energy $E_x$, can come into existence provided they annihilate within a ...
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Electromagnetic Unruh effect?

The Unruh temperature is given by $$T=\frac{\hbar\ a}{2\pi c k_B}.$$ If we have an electron field with charge $e$ and mass $m_e$ acted on by an electromagnetic field $\vec{E}$ then very naively maybe ...
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Lorentz transform in Unruh effect

I'm re-reading about the Unruh effect and while I broadly understand the concept of plugging through the coordinate transform and the Bogoliubov transformation, I'm curious as to whether there is a ...
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What is the Unruh temperature for an observer at near the speed of light?

I have read about the Unruh effect where an accelerated observer would experience a radiation that a non accelerated observer wouldn't. According to wikipedia the formula goes like this: My question ...
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Is there any relation between Casimir effect and Unruh radiation?

I hope this question is appropriate for this site. The question refers to the link: https://arxiv.org/abs/1302.2775 where it proposes that: Abstract: The property of inertia has never been fully ...
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Unruh effect and string theory?

My sincere apology if this question is not appropriate for this forum. Recently, I came across the Unruh radiation or Unruh effect. From the Wikipedia page https://en.wikipedia.org/wiki/Unruh_effect ...
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The relation between the Unruh effect and the Ehrenfest-Tolman effect

I am interested in the relation and, perhaps, the equivalence between two effects to do with temperature and gravity. The first one, the Unruh effect, states that the background black-body radiation, ...
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Existence of the Unruh effect

In the paper Quantum field aspect of Unruh problem (and others with similar approaches) Buchholz and Verch show that applying the rigorous algebraic approach to QFT, the derivation of the Unruh effect ...
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What does an accelerated body's *interaction* with Unruh radiation look like in an inertial frame?

(Note: I'm only considering flat spacetime in this question.) The Unruh effect is that the quantum state that looks like the vacuum in an inertial frame looks like a thermal bath of particles in a ...
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Why acceleration at the edge of the galaxy is lesser?

I was going through Modified Inertia using the Hubble Scale Casimir effect the theory is proposed by M.E. McCulloch. The theory says it can explain different anomalies such as EmDrive, Galactic edges,...
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Unruh effect, temperature and energy density

The Unruh effect basically states that an accelerated observer will see warm gas of particles following a blackbody distribution with some temperature T, where as an inertial observer would see none. ...