How hot is Schrödinger’s coffee?

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A group of scientists from the University of Exeter (University of Exeter) found new “uncertain relationships” that link the accuracy with which temperature can be measured, with the laws of mysterious quantum mechanics. If you measure the temperature of freshly brewed coffee with a conventional thermometer , you can get a value around 90 degrees Celsius plus or minus 0.5 degrees. The measurement error in this case arises from the fact that the level of mercury in the thermometer constantly fluctuates due to the constant collisions of mercury atoms as a result of their thermal motion.

The process of measuring temperature becomes more complicated and interesting when it comes to measuring the temperature of tiny objects, the dimensions of which are measured in hundreds, tens and units of nanometers.. Indeed, in order to measure the temperature of such objects, nanoscale thermometers consisting of only a few atoms are required .

Scientists from the University of Exeter, using theoretical calculations, have developed a tiny structure that allows you to measure the parameters of nanoscale thermometers and calibrate them with a sufficient level of accuracy. Using this kind of stand, they found out that the error in temperature measurements has a tendency to additional fluctuations, which is due to the influence of quantum effects. Like any quantum objects, these tiny thermometers can be in a state of superposition with respect to temperature, in other words, the thermometer itself can have and display two temperatures at once, for example 90.5 C and 89.5 C, just like the famous Schrödinger cat that is in superposition, which is both alive and dead at the same time.

“In addition to thermal noise that affects temperature measurements, the accuracy of these measurements makes a contribution to the state of quantum superposition,” says lead researcher Harry Miller, “And when the dimensions of the object and the thermometer itself approach the nanoscale level , the effect of quantum effects on measurement accuracy comes to the fore. ”

This discovery is important for scientists researching both the world of microscopic objects and the world of quantum mechanics. Having knowledge of quantum uncertainty in temperature measurement will allow scientists to optimize the structure of nanoscale thermometers so as to minimize the effect of quantum effects on the measurements made.

“This discovery is the first step towards creating new thermodynamic laws and concepts acting at the nanoscale level, where the laws of classical physics cease to work completely,” says Dr. Janet Anders.