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22/10/17/1523215 story

Ultra-Precise Quantum Thermometer to Measure Temperatures of Space and Time

posted by janrinok on Tuesday October 18 2022, @06:02AM   

Arthur T Knackerbracket has processed the following story:

An international team of scientists including experts from the University of Adelaide has designed a quantum thermometer to measure the ultra-cold temperatures of space and time predicted by Einstein and the laws of quantum mechanics.

The University of Adelaide's Dr. James Q. Quach, Ramsay Fellow, School of Physical Sciences and the Institute for Photonics and Advanced Sensing (IPAS), led the investigation.

"We have designed a quantum thermometer that can measure extremely small changes in temperature," he said. "The theoretical design of the quantum thermometer is based on the same technology used to build quantum computers."

Einstein predicted that the rate at which you perceive time to pass is dependent on the speed at which you are traveling: a person moving very fast ages at a slower rate than someone standing still. This led to his Theory of General Relativity, which says that space and time together act like a fabric that can flex and warp.

The relationship between temperature and acceleration is similar to the relationship between time and speed. Different observers moving at different acceleration would perceive different, albeit minute, difference in temperatures.

Journal Reference:
James Q. Quach, Timothy C. Ralph, and William J. Munro. Berry Phase from the Entanglement of Future and Past Light Cones: Detecting the Timelike Unruh Effect, Phys. Rev. Lett. 129, 160401 (DOI https://doi.org/10.1103/PhysRevLett.129.160401)

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Original Submission

• This hurts my head (Score: 1, Informative) by Anonymous Coward on Tuesday October 18 2022, @07:45PM

  by Anonymous Coward on Tuesday October 18 2022, @07:45PM (#1277292)

  TFA is very short on any interesting details, so I went to the paper:

  The Unruh effect is the intriguing idea that an accelerating observer will view the quantum vacuum as a thermal state [1]. It arises as a consequence of the theory of relativity applied to quantum mechanics: quantum states are dependent on the spacetime path of the observer.

  Here we propose an alternative and more practical stationary Λ system to measure the Unruh effect by making use of the entanglement between modes in the future and past lightcones.

  A uniformly accelerating observer is most conveniently described as a stationary observer in Rindler coordinates [25]. Here the Unruh effect arises as the result of spacelike entanglement between particles in the left and right Rindler wedges [1] (Fig. 1). Specifically, the vacuum state can be written as an entangled state between two sets of modes spanning the left and right Rindler wedges. As an accelerating observer is confined to just one of these wedges, tracing out the unobserved modes leads to the prediction that such an observer will see a thermalized vacuum. Recently, it has been shown that in theory one could write down the vacuum state similarly as entangled states between modes spanning the future and past light cones [26–28]. If an observer or detector is confined to a spacetime trajectory in one of these cones, tracing out the unobserved modes again will lead to a thermal vacuum state. Here we determine the GP for an observer on one of these trajectories. We demonstrate that the GP can be used to measure the timelike Unruh effect with current technology

  Conclusion.—We have shown how the Λ system can be used to detect the timelike Unruh effect that arises out of the entanglement between future and past light cones, with practical operating parameters.

  "Entanglement between future and past light cones" . . .

• Now featuring Quantum Technology [tm] ! (Score: 2) by Rupert Pupnick on Wednesday October 19 2022, @02:17AM

  by Rupert Pupnick (7277) on Wednesday October 19 2022, @02:17AM (#1277352) Journal

  "Einstein predicted that the rate at which you perceive time to pass is dependent on the speed at which you are traveling: a person moving very fast ages at a slower rate than someone standing still."

  Worst description of Special Relativity ever. From a website that calls itself "phys.org" no less.