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The New Scientist

Thermometer to measure coldest thing ever made

Jacob Aron

Published Jan 1, 2013• 0 citations
OpenAlex

Abstract

With a quantum thermometer, one can measure the temperature of the coldest thing in the universe. And this new ability could provide fresh insights into black holes. The coldest matter known is a Bose-Einstein condensate (BEC)--millions of atoms that act as a single quantum object when cooled inside a magnetic trap. Lab experiments have formed BECs at half a billionth of a degree above absolute zero. Ivette Fuentes at the University of Nottingham, UK, says that it's the coldest thing they can produce in the lab; the closest thing to absolute zero. Now Fuentes and her colleagues have come up with a way to measure the temperature of a BEC without releasing it. They suggest trapping a few probe atoms--using lasers rather than a magnet--and moving these through the BEC.

Related papers

Constucting a Magneto-optical Trap (MOT) as a means to Bose- Einstein Condensate (BEC)

Mulmat, Christian

This research was focused on the construction of a magneto-optical trap (MOT) to create a Bose-Einstein Condensate (BEC) of 87Rb. The BEC is the coldest of the five states of matter functioning at a minuscule temperature of nanokelvin. A BEC is as close as we can get to absolute zero. Thus making it a valuable tool for researching the fundamental physics of quantum systems. Our setup utilizes both a high pressure and low-pressure MOT. The high-pressure MOT initiates the process with a high vapor density allowing for better Rb collection. The trapped atoms are then transported to the low-pressure MOT where there are no other atoms. Rb atoms are further cooled to a Bose-Einstein condensate temperature and are moved with more current-carrying coils to the glass BEC chamber. In the BEC chamber all Rb atoms are identical at their lowest quantum state. Although the process can be phrased in a few short sentences the setup and characterization of the entire system takes months to years of construction. # 43- 46 Environmental Fellows Program: Student Practicums

•Oct 2, 2019•0 citations

How Bose–Einstein condensates keep revealing weird physics

Stephen Ornes

A Bose-Einstein condensate (BEC), the first of which was shown experimentally 22 years ago, isn’t your garden variety state of matter. It formed at a fraction above absolute zero and only in atoms that act like bosons, one of two types of fundamental particles. Bosons don’t follow the Pauli exclusion principle, which prohibits two particles from existing in the same quantum state. When bosonic atoms are cooled to form a condensate, they can lose their individuality. They behave like one big collective superatom, analogous to how photons become indistinguishable in a laser beam. But it’s even weirder than that. This velocity-distribution data for a gas of rubidium atoms confirmed the discovery of the Bose–Einstein condensate in 1995. In these three snapshots in time, atoms—cooled to near absolute zero—condensed from less dense areas on the left (red, yellow, and green) to very dense areas at the center and the right (blue and white). Image courtesy of NIST/JILA/CU-Boulder. “In a very good analogy, one can view a BEC as a bell, which begins to ring spontaneously when it is cooled below a certain temperature,” writes physicist Nick Proukakis at the Joint Quantum Centre Durham–Newcastle in the United Kingdom, in Universal Themes of Bose–Einstein Condensation , a forthcoming collection of research essays on progress in BECs (1). That behavior provides physicists with an extraordinary opportunity: to study bizarre quantum effects on a large scale, instead of having to probe individual particles. For the last two decades, physicists have treated BECs something like Play-Doh. They poke it, smash it, tickle it with lasers, and trap it in magnetic fields. They mix condensates together to see what happens, and use it to slow down light (2). They have observed strange behaviors that would have been impossible to predict even two decades ago: solids that flow …

Proceedings of the National Academy of Sciences•Jun 5, 2017•8 citations

Bose-Einstein Condensates Display Their First Tricks

Gary Taubes

A year ago this month, physicists first created a Bose-Einstein condensate, a state of matter in which a cloud of trapped atoms is cooled so close to absolute zero that their quantum-mechanical waves merge. But with barely 1000 atoms in a condensate that lasted just a few seconds, the researchers could do no more than say they'd done it. Now the field is being transformed by a new atom trap that can create condensates of 5 million sodium atoms that survive for half a minute and a new technique for imaging condensates without destroying them. Several research groups are now probing the size, growth rate, optical properties, and even the viscosity of this new form of matter.

Science•Jun 14, 1996•1 citation

Introduction

Sunipa Som

Bose Einstein Condensate (BEC) is the fifth state of matter in condensed matter physics. It is the most impressive example of quantum behaviour on a macroscopic scale but the most difficult state to observe. When low-density boson gas is cooled to a temperature nearly absolute zero, then BEC is formed. In this condition, the bosons have almost no free energy to move relative to each other. They clump together, come into the lowest quantum state, and behave as a single atom. Then microscopic quantum mechanical phenomena work on a macroscopic scale. This chapter summarizes the history and the developments regarding BEC with a brief discussion of the key scientists in this field. In the next section, the summary of the all chapters is given.

BENTHAM SCIENCE PUBLISHERS eBooks•Feb 21, 2024•0 citations

Quantum sensing of temperature close to absolute zero in a Bose-Einstein condensate

Ji-Bing Yuan, Bo Zhang, Ya‐Ju Song +3 more

We propose a theoretical scheme for quantum sensing of temperature close to absolute zero in a quasi-one-dimensional Bose-Einstein condensate (BEC). In our scheme, a single-atom impurity qubit is used as a temperature sensor. We investigate the sensitivity of the single-atom sensor in estimating the temperature of the BEC. We demonstrate that the sensitivity of the temperature sensor can saturate the quantum Cram\'er-Rao bound by means of measuring quantum coherence of the probe qubit. We study the temperature sensing performance by using quantum signal-to-noise ratio (QSNR). It is indicated that there is an optimal encoding time at which the QSNR can reach its maximum in the full-temperature regime. In particular, we find that the QSNR reaches a finite upper bound in the weak coupling regime even when the temperature is close to absolute zero, which implies that the sensing-error-divergence problem is avoided in our scheme. Our work opens a way for quantum sensing of temperature close to absolute zero in the BEC.

arXiv:2212.08237•Physical Review A•Jun 29, 2023•26 citations

From thermodynamics to thermometry with single-atom devices

Mark T. Mitchison

This thesis presents theoretical research on microscopic measuring devices and thermal machines constructed from single trapped atoms. We study several variants on this theme, with a particular emphasis on their application to ultracold atom physics. The first part of the thesis is about quantum refrigerators powered by thermal absorption rather than by external work. We propose and detail how such a machine may be practically constructed with a trapped atom placed inside an optical cavity, and employed to cool the atom close to absolute zero temperature using only collimated sunlight as an energy source. We then show that quantum absorption refrigerators in the strong-coupling regime exhibit coherent oscillations, thus enabling one to outperform a typical classical refrigerator by reaching lower temperatures than the steady state in a finite time using quantum coherence. The second part of the thesis studies the use of impurity atoms as probes of ultracold atomic gases. We discuss two different thermometry methods using impurities which are sensitive to temperature differences on the order of nanokelvin or less. We characterise the precision of the proposed thermometers by explicit calculations in the context of both weakly and strongly interacting atomic Bose gases. Finally, we study impurities immersed in a cold atomic Fermi gas realising a superfluid. We show that the impurities' energy dissipation rate probes the spectrum of density fluctuations in the gas, providing nondestructive access to various properties of the superfluid order parameter along the crossover from a Bardeen-Cooper-Schrieffer (BCS) state to a Bose-Einstein condensate (BEC).

•Sep 1, 2016•0 citations
With a quantum thermometer, one can measure the temperature of the coldest thing in the universe. And this new ability could provide fresh insights into black holes. The coldest matter known is a Bose-Einstein condensate (BEC)--millions of atoms that act as a single quantum object when cooled inside a magnetic trap. Lab experiments have formed BECs at half a billionth of a degree above absolute zero. Ivette Fuentes at the University of Nottingham, UK, says that it's the coldest thing they can produce in the lab; the closest thing to absolute zero. Now Fuentes and her colleagues have come up with a way to measure the temperature of a BEC without releasing it. They suggest trapping a few probe atoms--using lasers rather than a magnet--and moving these through the BEC.
This research was focused on the construction of a magneto-optical trap (MOT) to create a Bose-Einstein Condensate (BEC) of 87Rb. The BEC is the coldest of the five states of matter functioning at a minuscule temperature of nanokelvin. A BEC is as close as we can get to absolute zero. Thus making it a valuable tool for researching the fundamental physics of quantum systems. Our setup utilizes both a high pressure and low-pressure MOT. The high-pressure MOT initiates the process with a high vapor density allowing for better Rb collection. The trapped atoms are then transported to the low-pressure MOT where there are no other atoms. Rb atoms are further cooled to a Bose-Einstein condensate temperature and are moved with more current-carrying coils to the glass BEC chamber. In the BEC chamber all Rb atoms are identical at their lowest quantum state. Although the process can be phrased in a few short sentences the setup and characterization of the entire system takes months to years of construction. # 43- 46 Environmental Fellows Program: Student Practicums
A Bose-Einstein condensate (BEC), the first of which was shown experimentally 22 years ago, isn’t your garden variety state of matter. It formed at a fraction above absolute zero and only in atoms that act like bosons, one of two types of fundamental particles. Bosons don’t follow the Pauli exclusion principle, which prohibits two particles from existing in the same quantum state. When bosonic atoms are cooled to form a condensate, they can lose their individuality. They behave like one big collective superatom, analogous to how photons become indistinguishable in a laser beam. But it’s even weirder than that. This velocity-distribution data for a gas of rubidium atoms confirmed the discovery of the Bose–Einstein condensate in 1995. In these three snapshots in time, atoms—cooled to near absolute zero—condensed from less dense areas on the left (red, yellow, and green) to very dense areas at the center and the right (blue and white). Image courtesy of NIST/JILA/CU-Boulder. “In a very good analogy, one can view a BEC as a bell, which begins to ring spontaneously when it is cooled below a certain temperature,” writes physicist Nick Proukakis at the Joint Quantum Centre Durham–Newcastle in the United Kingdom, in Universal Themes of Bose–Einstein Condensation , a forthcoming collection of research essays on progress in BECs (1). That behavior provides physicists with an extraordinary opportunity: to study bizarre quantum effects on a large scale, instead of having to probe individual particles. For the last two decades, physicists have treated BECs something like Play-Doh. They poke it, smash it, tickle it with lasers, and trap it in magnetic fields. They mix condensates together to see what happens, and use it to slow down light (2). They have observed strange behaviors that would have been impossible to predict even two decades ago: solids that flow …
A year ago this month, physicists first created a Bose-Einstein condensate, a state of matter in which a cloud of trapped atoms is cooled so close to absolute zero that their quantum-mechanical waves merge. But with barely 1000 atoms in a condensate that lasted just a few seconds, the researchers could do no more than say they'd done it. Now the field is being transformed by a new atom trap that can create condensates of 5 million sodium atoms that survive for half a minute and a new technique for imaging condensates without destroying them. Several research groups are now probing the size, growth rate, optical properties, and even the viscosity of this new form of matter.
Bose Einstein Condensate (BEC) is the fifth state of matter in condensed matter physics. It is the most impressive example of quantum behaviour on a macroscopic scale but the most difficult state to observe. When low-density boson gas is cooled to a temperature nearly absolute zero, then BEC is formed. In this condition, the bosons have almost no free energy to move relative to each other. They clump together, come into the lowest quantum state, and behave as a single atom. Then microscopic quantum mechanical phenomena work on a macroscopic scale. This chapter summarizes the history and the developments regarding BEC with a brief discussion of the key scientists in this field. In the next section, the summary of the all chapters is given.
We propose a theoretical scheme for quantum sensing of temperature close to absolute zero in a quasi-one-dimensional Bose-Einstein condensate (BEC). In our scheme, a single-atom impurity qubit is used as a temperature sensor. We investigate the sensitivity of the single-atom sensor in estimating the temperature of the BEC. We demonstrate that the sensitivity of the temperature sensor can saturate the quantum Cram\'er-Rao bound by means of measuring quantum coherence of the probe qubit. We study the temperature sensing performance by using quantum signal-to-noise ratio (QSNR). It is indicated that there is an optimal encoding time at which the QSNR can reach its maximum in the full-temperature regime. In particular, we find that the QSNR reaches a finite upper bound in the weak coupling regime even when the temperature is close to absolute zero, which implies that the sensing-error-divergence problem is avoided in our scheme. Our work opens a way for quantum sensing of temperature close to absolute zero in the BEC.
This thesis presents theoretical research on microscopic measuring devices and thermal machines constructed from single trapped atoms. We study several variants on this theme, with a particular emphasis on their application to ultracold atom physics. The first part of the thesis is about quantum refrigerators powered by thermal absorption rather than by external work. We propose and detail how such a machine may be practically constructed with a trapped atom placed inside an optical cavity, and employed to cool the atom close to absolute zero temperature using only collimated sunlight as an energy source. We then show that quantum absorption refrigerators in the strong-coupling regime exhibit coherent oscillations, thus enabling one to outperform a typical classical refrigerator by reaching lower temperatures than the steady state in a finite time using quantum coherence. The second part of the thesis studies the use of impurity atoms as probes of ultracold atomic gases. We discuss two different thermometry methods using impurities which are sensitive to temperature differences on the order of nanokelvin or less. We characterise the precision of the proposed thermometers by explicit calculations in the context of both weakly and strongly interacting atomic Bose gases. Finally, we study impurities immersed in a cold atomic Fermi gas realising a superfluid. We show that the impurities' energy dissipation rate probes the spectrum of density fluctuations in the gas, providing nondestructive access to various properties of the superfluid order parameter along the crossover from a Bardeen-Cooper-Schrieffer (BCS) state to a Bose-Einstein condensate (BEC).