Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Atom-chip Bose-Einstein condensation in a portable vacuum cell

Shengwang Du, Matthew B. Squires, Yutaka Imai, Leslie Czaia, R. A. Saravanan, Victor M. Bright, Jakob Reichel, Theodor W. Hänsch, Dana Z. Anderson

Published Nov 10, 2004• 122 citations
Publisher

Abstract

A $^{87}\mathrm{Rb}$ Bose-Einstein condensate (BEC) is produced in a portable atom-chip system less than $30\ifmmode\times\else\texttimes\fi{}30\ifmmode\times\else\texttimes\fi{}15\phantom{\rule{0.3em}{0ex}}\mathrm{cm}$, where the ultrahigh vacuum is maintained by a small, $8\phantom{\rule{0.3em}{0ex}}\mathrm{L}∕\mathrm{s}$, ion pump and nonevaporable getter. An aluminum nitride chip with lithographically patterned copper is used to seal the vacuum system, provide the electrical feedthroughs, and create the magnetic trap potentials. All cooling and trapping processes occur $0.6--2.5\phantom{\rule{0.3em}{0ex}}\mathrm{mm}$ from ambient laboratory air. A condensate of about 2000 $^{87}\mathrm{Rb}$ atoms in $F=2,{m}_{F}=2$ is achieved after $4.21\phantom{\rule{0.3em}{0ex}}\mathrm{s}$ of rf forced evaporation. A magneto-optical trap lifetime of $30\phantom{\rule{0.3em}{0ex}}\mathrm{s}$ indicates the vacuum near the chip surface is about ${10}^{\ensuremath{-}10}\phantom{\rule{0.3em}{0ex}}\text{torr}$. This work suggests that a chip-based BEC-compatible vacuum system can occupy a volume of less than $0.5\phantom{\rule{0.3em}{0ex}}\mathrm{L}$.

DOI
10.1103/physreva.70.053606

Related papers

Investigating the dynamics of a Bose Einstein condensate on an atom chip

I J M Barr

In this thesis I discuss work that has been carried out on the dynamics of a Bose Einstein condensate of Rb 87 produced near an atom chip. A Bose Einstein Condensate (BEC) is a quantum state of matter where a single quantum state becomes occupied by a macroscopic number of identical Bosons. In our case this is achieved by cooling a system of trapped identical rubidium 87 atoms to its ground state. To reach temperatures of condensation we initially laser cool atoms from room temperature, before loading them into a magnetic trap. The magnetic trap is produced through a combination of uniform magnetic fields from coils outside our vacuum chamber and currents running through wires on an atom chip. The atom chip is a microfabricated device, produced by a coating a silicon chip with a thin layer of gold and etching wires into it. Together, these fields create a magnetic field minimum 120μm from the surface of the chip which can be used to confine low field seeking hyperfine states of the atom in an elongated harmonic trap. Once the atoms are confined in the magnetic trap we used force evaporative cooling out to reach the phase space densities required for Bose Einstein condensation. The BEC is used to investigate the relative dynamics between the fraction of the atoms in the condensate to those not in the condensate. Our atom chip provided a suitable environment to investigate this due to fragmentation of the magnetic potential close to the chip. Small imperfections in the wires on our atom chip mean that the trapping potential isn’t smooth. Small regions of higher trapping frequency - or fragments - are formed. Due to the small size of these fragments it is possible to find a position where a condensate can form in the fragment, and see a potential of high frequency, whereas a non-condensed atom will see a lower frequency potential. We exploit this to set the condensed fraction moving relative to the non condensed part and investigate the subsequent damping of their motion relative to each other.

•May 1, 2015•2 citations

An apparatus for the production of Bose-Einstein condensates in tunable geometries on a chip

Thomas J. Barrett

Atom chips are an excellent tool for studying ultracold degenerate quantum gases, due to the high degree of controllability afforded by the precise potentials generated from the current-carrying microfabricated wires on the chip surface. The geometries of the trapping potentials are inherently capable of realising extreme aspect ratios, and therefore creating model systems with effectively reduced dimensionality, particularly the theoretically-tractable one-dimensional Bose gas. In addition, the temporal tunability makes it possible to impart non-adiabatic changes on the trapping potentials, allowing experimental investigation of samples which have been brought out of equilibrium - a situation which is not fully theoretically understood. This thesis describes the implementation, development and characterisation of an experimental system for producing the first Bose-Einstein condensates of atomic rubidium 87 gas trapped on the surface of an atom chip in Nottingham. Such an apparatus is very complex and requires careful characterisation in order to run in a stable and reliable way. Details of the experimental setup are thoroughly outlined, including the vacuum system, lasers, electronics, computer control and timing, and the optical imaging system. A newly installed compact two-dimensional magneto-optical trap provides an loading rate of 5e7 atoms per second for loading a three-dimensional mirror-magneto-optical trap with 1.5e8 atoms, at a temperature of 300uK within 10s. The cloud is then sub-Doppler cooled to 50uK, and spin-polarised with 96% purity into the |F=2,mF=+2> ground state within 5ms, in preparation for loading a purely magnetic trap. A millimeter sized copper Z-shaped conductor located beneath the atom chip surface creates a Ioffe-Pritchard magnetic trap, into which the laser cooled cloud is loaded with 70% efficiency, and can be held with a vacuum-limited lifetime of 40s. Evaporative cooling then pre-cools the sample to below 20uK within 10s, to allow the subsequent loading into potentials created by the atom chip with 100% efficiency. A final evaporation stage then cools the cloud below the phase transition temperature of 800nK, resulting finally in pure BECs with $10^5$ atoms confined using the atom chip. Key measurements of various properties of the trapped condensates are presented, which are important in order to characterise the system fully, and to compare with theoretical expectations. In particular, included are the variation of condensate fraction with temperature, the BEC expansion dynamics, and the condensate lifetime in the trap, for example. Finally, it is demonstrated how BECs can be produced on the atom chip without the use of external macroscopic coils, achieved by using novel, integrated sheet structures located beneath the chip surface - unique to this experimental system - to create the necessary bias fields.

•Jul 12, 2017•0 citations

Bose-Einstein Condensation in a Surface Microtrap

Herwig Ott, József Fortágh, G. Schlotterbeck +2 more

Bose-Einstein condensation has been achieved in a magnetic surface microtrap with 4 x 10(5) (87)Rb atoms. The strongly anisotropic trapping potential is generated by a microstructure which consists of microfabricated linear copper conductor of widths ranging from 3 to 30 microm. After loading a high number of atoms from a pulsed thermal source directly into a magneto-optical trap the magnetically stored atoms are transferred into the microtrap by adiabatic transformation of the trapping potential. In the microtrap the atoms are cooled to condensation using forced rf-evaporation. The complete in vacuo trap design is compatible with ultrahigh vacuum below 2 x 10(-11) mbar.

arXiv:cond-mat/0109322•Physical Review Letters•Nov 13, 2001•375 citations

Progress towards Bose-Einstein condensation on an atom chip as a functional testbed for experiments aboard the orbital NASA Cold Atom Laboratory

Daniel Paseltiner

Since their initial production in 1995, the study of Bose-Einstein Condensates (BECs) has offered exciting new insights into many fields including quantum mechanics and solid state physics. Atom chips, non-conducting surfaces with conducting lithographic traces printed on them, have proven successful in generating lower power magnetic traps for the formation of BECs. The combination of their lower power consumption, small form factor, and dense traps makes atom chips a promising way to face a ubiquitous challenge in the study of BECs: the effect of the earth’s gravitational field. To avoid these effects the NASA Cold Atom Laboratory aims to create BECs aboard the International Space Station (ISS) using an atom chip. This thesis presents the development of a similar atom chip based BEC experiment at Bates College, which will serve as a functional testbed for future research aboard the ISS. Both a theoretical background and a description of the experimental process by which a BEC is formed on an atom chip are provided. This process is primarily driven by laser cooling and magnetic trapping techniques. A 2D+ Magneto-Optical Trap (MOT), loaded from vapor pressure, is used as a slowed source of 87Rb in order to create a 3D MOT. We present measurements of the performance of both MOTs, and outline a path forward to condensation on the chip-based magnetic trap through use of radiofrequency evaporative cooling.

•Jan 1, 2016•0 citations

Bose–Einstein condensation on an atom chip

Yan Bo, Cheng Feng, Ke Min +3 more

This paper reports an experiment of creating Bose–Einstein condensate (BEC) on an atom chip. The chip-based Z-wire current with a homogeneous bias magnetic field creates a tight magnetic trap, which allows for a fast production of BEC. After a 4.17-s forced radio frequency evaporative cooling, a condensate with about 3000 atoms appears. The transition temperature is about 300 nK. This compact system is quite robust, allowing for versatile extensions and further studying of BEC.

arXiv:0812.2711•Chinese Physics B•Sep 29, 2009•15 citations

A compact, transportable, microchip-based system for high repetition rate production of Bose–Einstein condensates

Daniel Farkas, Kai Hudek, Evan A. Salim +3 more

We present a compact, transportable system that produces Bose–Einstein condensates near the surface of an integrated atom microchip. The system occupies a volume of 0.4 m3, operates at a repetition rate as high as 0.3 Hz, and consumes an average power of 525 W. Evaporative cooling in a chip trap with trap frequencies of several kilohertz leads to nearly pure condensates containing 1.9×104 R87b atoms. Partial condensates are observed at a temperature of 1.58(8) μK, close to the theoretical transition temperature of 1.1 μK.

arXiv:0912.0553•Applied Physics Letters•Mar 1, 2010•67 citations
A 87Rb^{87}\mathrm{Rb}87Rb Bose-Einstein condensate (BEC) is produced in a portable atom-chip system less than 30\ifmmode×\else\texttimes\fi30\ifmmode×\else\texttimes\fi15cm30\ifmmode\times\else\texttimes\fi{}30\ifmmode\times\else\texttimes\fi{}15\phantom{\rule{0.3em}{0ex}}\mathrm{cm}30\ifmmode×\else\texttimes\fi30\ifmmode×\else\texttimes\fi15cm, where the ultrahigh vacuum is maintained by a small, 8L∕s8\phantom{\rule{0.3em}{0ex}}\mathrm{L}∕\mathrm{s}8L∕s, ion pump and nonevaporable getter. An aluminum nitride chip with lithographically patterned copper is used to seal the vacuum system, provide the electrical feedthroughs, and create the magnetic trap potentials. All cooling and trapping processes occur 0.6−−2.5mm0.6--2.5\phantom{\rule{0.3em}{0ex}}\mathrm{mm}0.6−−2.5mm from ambient laboratory air. A condensate of about 2000 87Rb^{87}\mathrm{Rb}87Rb atoms in F=2,mF=2F=2,{m}_{F}=2F=2,mF​=2 is achieved after 4.21s4.21\phantom{\rule{0.3em}{0ex}}\mathrm{s}4.21s of rf forced evaporation. A magneto-optical trap lifetime of 30s30\phantom{\rule{0.3em}{0ex}}\mathrm{s}30s indicates the vacuum near the chip surface is about 10\ensuremath−10torr{10}^{\ensuremath{-}10}\phantom{\rule{0.3em}{0ex}}\text{torr}10\ensuremath−10torr. This work suggests that a chip-based BEC-compatible vacuum system can occupy a volume of less than 0.5L0.5\phantom{\rule{0.3em}{0ex}}\mathrm{L}0.5L.
In this thesis I discuss work that has been carried out on the dynamics of a Bose Einstein condensate of Rb 87 produced near an atom chip. A Bose Einstein Condensate (BEC) is a quantum state of matter where a single quantum state becomes occupied by a macroscopic number of identical Bosons. In our case this is achieved by cooling a system of trapped identical rubidium 87 atoms to its ground state. To reach temperatures of condensation we initially laser cool atoms from room temperature, before loading them into a magnetic trap. The magnetic trap is produced through a combination of uniform magnetic fields from coils outside our vacuum chamber and currents running through wires on an atom chip. The atom chip is a microfabricated device, produced by a coating a silicon chip with a thin layer of gold and etching wires into it. Together, these fields create a magnetic field minimum 120μm from the surface of the chip which can be used to confine low field seeking hyperfine states of the atom in an elongated harmonic trap. Once the atoms are confined in the magnetic trap we used force evaporative cooling out to reach the phase space densities required for Bose Einstein condensation. The BEC is used to investigate the relative dynamics between the fraction of the atoms in the condensate to those not in the condensate. Our atom chip provided a suitable environment to investigate this due to fragmentation of the magnetic potential close to the chip. Small imperfections in the wires on our atom chip mean that the trapping potential isn’t smooth. Small regions of higher trapping frequency - or fragments - are formed. Due to the small size of these fragments it is possible to find a position where a condensate can form in the fragment, and see a potential of high frequency, whereas a non-condensed atom will see a lower frequency potential. We exploit this to set the condensed fraction moving relative to the non condensed part and investigate the subsequent damping of their motion relative to each other.
Atom chips are an excellent tool for studying ultracold degenerate quantum gases, due to the high degree of controllability afforded by the precise potentials generated from the current-carrying microfabricated wires on the chip surface. The geometries of the trapping potentials are inherently capable of realising extreme aspect ratios, and therefore creating model systems with effectively reduced dimensionality, particularly the theoretically-tractable one-dimensional Bose gas. In addition, the temporal tunability makes it possible to impart non-adiabatic changes on the trapping potentials, allowing experimental investigation of samples which have been brought out of equilibrium - a situation which is not fully theoretically understood. This thesis describes the implementation, development and characterisation of an experimental system for producing the first Bose-Einstein condensates of atomic rubidium 87 gas trapped on the surface of an atom chip in Nottingham. Such an apparatus is very complex and requires careful characterisation in order to run in a stable and reliable way. Details of the experimental setup are thoroughly outlined, including the vacuum system, lasers, electronics, computer control and timing, and the optical imaging system. A newly installed compact two-dimensional magneto-optical trap provides an loading rate of 5e7 atoms per second for loading a three-dimensional mirror-magneto-optical trap with 1.5e8 atoms, at a temperature of 300uK within 10s. The cloud is then sub-Doppler cooled to 50uK, and spin-polarised with 96% purity into the |F=2,mF=+2> ground state within 5ms, in preparation for loading a purely magnetic trap. A millimeter sized copper Z-shaped conductor located beneath the atom chip surface creates a Ioffe-Pritchard magnetic trap, into which the laser cooled cloud is loaded with 70% efficiency, and can be held with a vacuum-limited lifetime of 40s. Evaporative cooling then pre-cools the sample to below 20uK within 10s, to allow the subsequent loading into potentials created by the atom chip with 100% efficiency. A final evaporation stage then cools the cloud below the phase transition temperature of 800nK, resulting finally in pure BECs with 10510^5105 atoms confined using the atom chip. Key measurements of various properties of the trapped condensates are presented, which are important in order to characterise the system fully, and to compare with theoretical expectations. In particular, included are the variation of condensate fraction with temperature, the BEC expansion dynamics, and the condensate lifetime in the trap, for example. Finally, it is demonstrated how BECs can be produced on the atom chip without the use of external macroscopic coils, achieved by using novel, integrated sheet structures located beneath the chip surface - unique to this experimental system - to create the necessary bias fields.
Bose-Einstein condensation has been achieved in a magnetic surface microtrap with 4 x 10(5) (87)Rb atoms. The strongly anisotropic trapping potential is generated by a microstructure which consists of microfabricated linear copper conductor of widths ranging from 3 to 30 microm. After loading a high number of atoms from a pulsed thermal source directly into a magneto-optical trap the magnetically stored atoms are transferred into the microtrap by adiabatic transformation of the trapping potential. In the microtrap the atoms are cooled to condensation using forced rf-evaporation. The complete in vacuo trap design is compatible with ultrahigh vacuum below 2 x 10(-11) mbar.
Since their initial production in 1995, the study of Bose-Einstein Condensates (BECs) has offered exciting new insights into many fields including quantum mechanics and solid state physics. Atom chips, non-conducting surfaces with conducting lithographic traces printed on them, have proven successful in generating lower power magnetic traps for the formation of BECs. The combination of their lower power consumption, small form factor, and dense traps makes atom chips a promising way to face a ubiquitous challenge in the study of BECs: the effect of the earth’s gravitational field. To avoid these effects the NASA Cold Atom Laboratory aims to create BECs aboard the International Space Station (ISS) using an atom chip. This thesis presents the development of a similar atom chip based BEC experiment at Bates College, which will serve as a functional testbed for future research aboard the ISS. Both a theoretical background and a description of the experimental process by which a BEC is formed on an atom chip are provided. This process is primarily driven by laser cooling and magnetic trapping techniques. A 2D+ Magneto-Optical Trap (MOT), loaded from vapor pressure, is used as a slowed source of 87Rb in order to create a 3D MOT. We present measurements of the performance of both MOTs, and outline a path forward to condensation on the chip-based magnetic trap through use of radiofrequency evaporative cooling.
We present a compact, transportable system that produces Bose–Einstein condensates near the surface of an integrated atom microchip. The system occupies a volume of 0.4 m3, operates at a repetition rate as high as 0.3 Hz, and consumes an average power of 525 W. Evaporative cooling in a chip trap with trap frequencies of several kilohertz leads to nearly pure condensates containing 1.9×104 R87b atoms. Partial condensates are observed at a temperature of 1.58(8) μK, close to the theoretical transition temperature of 1.1 μK.