Soliton Project: News


Posted on: 2015-02-24


Apparatus upgrade
April 2014
The laboratory is currently undergoing its major upgrade which includes a new magnetic coils setup, a new optical setup, and new LabVIEW control software. This upgrade will provide greater control in solitary wave production, a more flexible control in trap geomtery and trap frequencies, as well as a better optical access for imaging and future experiments. This is an important step towards atom-surface experiments.
Manfred attended YAO2014
April 2014
Manfred recently attended the annual Young Atomic Opticians (YAO) conference held in the Institute of Photonic Sciences (ICFO) in Barcelona. He presented his talk entitled 'Quantum reflection of tunable matter-wave from a narrow Gaussian potential' where he discussed the latest results including the quantum reflection of the bright solitary wave from a narrow Gaussian potential well.
Dr. Ana Rakonjac starts her postdoc
December 2013
Welcome to Dr. Ana Rakonjac who joins us from the University of Otago. Ana completed her Ph.D. in the group of Niels Kjaergaard where she worked on the design and construction of an optical collider for use in the study of ultracold collisions.
Observation of quantum reflection from a Gaussian well
November 2013
We have observed quantum reflection from an attractive potential well, formed from a red-detuned laser beam. Preliminary work was carried out in March with more measurements following towards the end of the year.

The image to the right shows a slow moving (1mm/s) soliton which reaches the position of the barrier and splits. A fraction of the atoms are reflected (R), a smaller number remain trapped at the location of the barrier (shown by the arrow) and the remainder travel through (T).
Simon and Anna attend ICOLS 2013
June 2013
This summer Simon and Anna attended the International Confernce on Laser Spectroscopy, ICOLS 2013, held in Berkeley, California. They presented posters on both the soliton and RbCs projects, pdfs of which can be found on the project front pages.

There was also time for a bit of sightseeing and to visit Sylvi (the soliton project's first graduate) at her new lab at UCLA where she joins Wes Campbell's ion trapping group.
Soliton formation paper published in Nature Communications  
May 2013
Our paper, Controlled formation and reflection of a bright solitary matter-wave, has been published in Nature Communications. The article is open access and can be found online here.
Soliton formation paper submitted
January 2013
Our latest paper detailing the formation of bright matter-wave solitons is now available on the arXiv. Here we describe the loading of a BEC into the optical waveguide and demonstrate the tunable nature of the atomic interactions, controlling the expansion of the condensate as it propagates. By tuning the interactions to be attractive, we are able to reduce the axial expansion of the wavepacket to zero. This lack of dispersion with time indicates the formation of a bright solitary matter-wave. In addition, we present the controlled reflection of a solitary wave from a broad repulsive Gaussian barrier and give an outlook to future work.

Shown to the right is the propagation in the waveguide: (a) As a repulsive BEC propagates along the waveguide the atomic interactions cause the condensate to spread, leading to a drop in optical depth. (b) In contrast, the attractive interactions present in a bright solitary matter-wave hold the atomic wavepacket together as it propagates, maintaining its shape with time. Crosscuts shown are the horizontal optical depth profiles of the condensates after 140 ms propagation time along the waveguide.
Anna passes her viva!
January 2013
Anna successfully defended her thesis on 9th January and became the second graduate of the soliton project! Celebrations included champagnes, cakes, and of course, the traditional German PhD hat made by Sylvi! Her thesis titled 'Formation of bright solitary matter-waves' will be available soon.

Congratulations!
Narrow attractive barrier characterized
December 2012
We have installed and characterized the narrow light barrier in preparation for quantum reflection experiment using solitons. The barrier, in a form of light sheet, is formed using an 852nm laser beam and focussed with a combination of cylindrical lens and aspheric lens with NA = 0.488. With a maximum power of 14mW, we have been able to trap 85Rb atoms at the tightly focussed waist which allows us to align and characterize the barrier inside the science cell. The narrow waist is measured to be 2.7µm.
Book chapter submitted - "Bright solitary matter waves: formation, stability and interactions"
September 2012
We have submitted a chapter on bright solitary matter waves for inclusion in a book edited by Boris Malomed on the topic of "Spontaneous Symmetry Breaking, Self-Trapping, and Josephson Oscillations in Nonlinear Systems". The work is a collaboration with Tom Billam, now at the University of Otago, and Nick Parker, a Newcastle based member of the newly formed Joint Quantum Centre (JQC) Durham-Newcastle. The manuscript is available on the ArXiv
Anna gives presentation at Photon 12
September 2012
Anna presented our latest results from the project in a talk entitled "Controlled formation and reflection of bright matter-wave solitons" at Photon 12, the IOP's premier conference in optics and photonics, hosted in Durham.
Simon and Anna attend ICAP 2012
July 2012
Simon and Anna both attended the ICAP 2012 conference, this year taking place in Palaiseau, France. Not only was this an opportunity to present the most recent results from the soliton and RbCs projects, but also a great chance to catch up with Sylvi and find out all about the escapades of an ion trapper!

The soliton poster, presented by Anna, can be found here.
Tim wins poster presentation prize at EGAS44 in Gothenburg, Sweden
July 2012
Tim attended the EGAS44 conference in Gothenburg, Sweden to present a poster of recent work that has been undertaken within the Soliton Project. At the end of the conference he was awarded the prize for the best presentation of a poster by a PhD student at EGAS. Click here to see the poster.
Reflection of a soliton from a repulsive Gaussian barrier
June 2012
We have observed the reflection of a bright matter-wave soliton from a repulsive Gaussian barrier. Following the reflection the soliton maintains its shape, continuing to propagate without dispersion. The image shows a soliton propagating along the waveguide unobstructed (left) and with the barrier present (right).

The barrier is formed using a 532nm laser beam, focussed to 130µm with a power of 1.75W. As the barrier is significantly wider than the soliton the system remains entirely classical. The next step will be to implement much narrower barriers, comparable to or less than the soliton width (10µm).
First observation of bright matter wave solitons
May 2012
After successfully loading atoms into the waveguide we have been able to create our first bright matter wave solitons! Shown to the right is a soliton propagating over a distance of around 1mm along the waveguide in 150ms.

We initially create a BEC in our crossed dipole trap. We then ramp the magnetic bias field to bring the scattering length close to zero. Following the ramp we rapidly switch the cross trap off and the waveguide on. Finally, we jump the scattering length to a small, negative value and allow the wavepacket to propagate along the beam.
85Rb BEC paper published  
May 2012
Our paper detailing the creation of our 85Rb BEC, Bose-Einstein condensation of 85Rb by direct evaporation in an optical dipole trap, has been published in Physical Review A. For the full abstract see the publications page.
Atoms in the waveguide
April 2012
We have made our first steps towards creating a soliton in a quasi-1D trap by loading a cold cloud of atoms (1 µK) into a waveguide. Time of flight expansion is shown with the waveguide on and off. We have also seen the first signs of a BEC in the waveguide by observing the tunable interactions of the cloud.
85Rb BEC paper submitted  
March 2012
Details of our 85Rb BEC can now be found in our paper, "Bose-Einstein condensation of 85Rb by direct evaporation in an optical dipole trap ". We present the method used to reach BEC, evidence of the tunable atomic interaction in the condensate and describe our future plans to transfer the BEC into an optical waveguide to investigate the formation of bright matter-wave solitons.
Tuning the interaction strength of a Rb BEC
March 2012
We are pleased to announce our first observation of tunable interactions in our 85Rb BEC. We compared the time of flight expansion (top left) of a thermal cloud (red circles) with that of a BEC (black squares) around a Feshbach resonance. To the left of a = 0 (red dashed line) we observe increasing repulsive interactions resulting in a five fold increase in the width of the BEC. A thermal cloud at 150 nK sees very little change in width around the Feshbach resonance. Five sample images show the dramatic increase in width for large respulsive interactions.

We also induced a breathing mode in the condensate (top right) at √5 x trap frequency by making a sudden change in the scattering length.
85Rb BEC!
January 2012
We are delighted to announce the creation of our first 85Rb BEC. First observed on 7th January 2012, the condensate is produced in a crossed dipole trap using a magnetic field gradient to levitate the atoms. Once loaded, evaporation in the dipole trap is carried out by reducing the beam intensities whilst tuning a magnetic bias field in order to exploit the suppression of inelastic loss near the Feshbach resonance in the F=2, mF=-2 state.

Using this single species cooling technique, our early experiments show pure condensate can be produced with ~30,000 atoms.

Apparatus paper published  
January 2012
Our paper describing the experimental setup, Magnetic transport apparatus for the production of ultracold atomic gases in the vicinity of a dielectric surface, has been published in Review of Scientific Instruments. For the full abstract see the publications page.
87Rb in an optical lattice
December 2011
We have loaded and condensed 87Rb in an optical lattice produced by our crossed dipole trap. As our trap is formed by producing a 'bow-tie' with a single beam, by rotating the polarisation of the beam as it enters the science cell it is possible to produce an optical lattice due to the interference between the two beams of the cross trap.

By condensing in the lattice and imaging from above it is possible to see the momentum distribution in the lattice. Once released from the trap the wave packets from each site are able to expand and interfere with each other producing the sort of peaks shown in the top image. By pulsing the lattice back on again for a short time it is also possible to see evidence of Kaptiza Dirac scattering (as shown in the lower two images).

Sylvi in Australia
November 2011
After successfully relocating to the other side of the world, Sylvi's been busy getting to know the locals! Adventuring aside, she's still found time for a quick coffee in the lab....

Details of Sylvi's new project at Griffith University can be found here.

Celebrations continue
September 2011
Why stop at one party when you can have two?! To mark Sylvi's viva Team Cornish (this time complete with Simon) took a trip to the Seven Stars to celebrate with the newest Doctor in town!
Sylvi's viva
September 2011
On 30th September Sylvi became the first official graduate of the soliton project! Durham also got to witness a more traditional German celebration, complete with PhD hat! Congratulations Sylvi and good luck in Brisbane!
Apparatus paper submitted
September 2011
Details of the experimental apparatus can now be found in our latest paper, "Magnetic transport apparatus for the production of ultracold atomic gases in the vicinity of a dielectric surface ". We present an apparatus designed for studies of atom-surface interactions using quantum degenerate gases of 85Rb and 87Rb in the vicinity of a room temperature dielectric surface. The surface to be investigated is a super-polished face of a glass Dove prism mounted in a glass cell under ultra-high vacuum (UHV). To maintain excellent optical access to the region surrounding the surface magnetic transport is used to deliver ultracold atoms from a separate vacuum chamber housing the magneto-optical trap (MOT). We present a detailed description of the vacuum apparatus highlighting the novel design features; a low profile MOT chamber and the inclusion of an obstacle in the transport path. We report the characterization and optimization of the magnetic transport around the obstacle, achieving transport efficiencies of 70% with negligible heating. Finally we demonstrate the loading of a hybrid optical-magnetic trap with 87Rb and the creation of Bose-Einstein condensates via forced evaporative cooling close to the dielectric surface.
Emily Barnard completes her summer project
August 2011
Having spent eights weeks with the soliton group Emily Barnard, from Durham University, has now completed her project. The intention of the project was to measure a number of properties of a broad area infrared diode laser (evanescent laser) that would be used to reflect cold atoms from the surface of our prism. The project included two classic physics experiments. The first of these was to build an Michelson interferometer to determine the coherence length of the laser. The beauty of this experiment was that useful information about the laser beam could be determined using simple optics and an old video camera in night vision mode. The interference patterns recorded by the camera were then analysed on a computer using MATLAB. A second experiment involved using a diffraction grating. The spread of frequencies of the evanescent laser and a single mode laser were compared by taking an image using the video camera and again analysing the image on a computer using MATLAB. Emily presented a talk of her findings to the Atmol group, which can be found here. Funding was provided by the Nuffield Foundation. Top: The spectral intensity distribution of the evanescent laser as a function of laser current. Bottom left: Emily with the experiment. Bottom right: An example interference fringe pattern due to the interferometer.
Guided transport paper submitted
August 2011
Our latest paper, "Guided transport of ultracold gases of rubidium upto a room-temperature dielectric surface" has been submitted! We report on the guided transport of an atomic sample along an optical waveguide up to a room-temperature dielectric surface. The technique exploits a simple hybrid trap consisting of a single beam dipole trap positioned ~125 μm below the field zero of a magnetic quadrupole potential. Transportation is realised by applying a moderate bias field (<12 G) to displace the magnetic field zero along the axis of the dipole trap. We use the technique to demonstrate that atomic gases may be precisely positioned at controlled distances from the surface with negligible heating or loss. This work forms an excellent basis for future studies of atom-surface interactions using ultracold atomic gases.
IPG laser installed  
July 2011
Our new dipole trapping laser has arrived and is installed on the vacuum table! Providing 15 W of power at 1064 nm it will allow us to create larger volume traps whilst maintaining our current trap depth. We'll also be using the new laser to produce a crossed dipole trap, allowing us to apply a bias field (around 160 G) to search for the Feshbach resonance in the 85Rb F=2, mF=-2 state.
Sylvi submitted!!
June 2011
After three and a half years of designing, building and optimising, Sylvi, the first student on the soliton project, has submitted her thesis entitled "Experiments on ultracold quantum gases of 85Rb and 87Rb". She'll be staying with the soliton project a little while longer before making her escape for sunnier climes down-under!
Anna and Simon at ICOLS 2011
May 2011
In May Anna and Simon attended the 20th International Conference on Laser Spectroscopy, ICOLS 2011, in Aerzen, Germany, presenting posters on both the soliton and mixture projects.
Merging paper published
May 2011
Our paper entitled "Magnetic merging of ultracold atomic gases of 85Rb and 87Rb" has been published in PRA. The technique allows the controlled production of isotopic mixtures of Rb and requires only two lasers.
Sylvi and Simon attend FOMO 2011
March 2011
Sylvi and Simon attended the 'Frontiers in Matter Wave Optics' (FOMO 2011) conference in Tirol. The poster they presented can be found here. There was also plenty of time to get in some serious skiing!
Faraday paper published
January 2011
Our paper on locking off resonance using the Faraday effect has been published in Optics Letters. You can find it here.
Merging paper submitted!
November 2010
We have submitted a paper entitled "Magnetic merging of ultracold atomic gases of 85Rb and 87Rb". We present a detailed analysis of the combined magnetic field potential as the two traps are brought together which predicts a clear optimum trajectory for the merging. We verify this prediction experimentally using 85Rb and find that the final atom number in the merged trap is maximised with minimal heating by following the predicted optimum trajectory.
87Rb BEC in the single beam trap
September 2010
We have produced our first BEC of 87Rb using our hybrid optical and magnetic trap. Using a single dipole beam, closed off with a magnetic quadrupole trap, we are able to produce condensates of ~ 1.5 x 106 atoms.
First observation of 87Rb in the dipole trap
July 2010
We have trapped 87Rb in our dipole beam, resulting in an elongated atom cloud due to reduced trapping (using magnetic fields) along the axial direction.
Merging of both isotopes of rubidium achieved
July 2010
We have now managed to merge both 85Rb and 87Rb, creating a mixture of these two isotopes. This is a demonstration of how multiple loading can achieve mixtures with a single laser system, by adjusting laser frequencies in between loads.
Faraday paper submitted
July 2010
We have submitted a paper entitled "Off resonance laser frequency stabilization using the Faraday effect". We have demonstrated the ability to lock both red and blue detuned (up to 14 GHz) from resonance, using the Faraday effect in a heated vapour cell.
Multiple loading of 85Rb optimised
June 2010
Through experimental optimisation we have shown, perhaps surprisingly, that our basic 1D model is an excellent indicator of where optimal merging occurs. The model only takes account of the potentials and does not model any dynamics, yet the inset shows how the best experimental ramps (indicated by the large arrow). The main plot shows how merging improves as we scan a magnetic field gradient ramp through the safe region (large arrow).
Sylvi in Germany!
June 2010
Sylvi attended the International Research School on Frontiers in Matter Wave Interferometry in Bad Honnef. Here she presented the long term goals of the soliton project to other attendees of the school.
First observation of two merged 85Rb atomic clouds
May 2010
By applying a change in magnetic field gradient to one of our coils while we merge two quadrupole traps, both of which contain 85Rb atoms, we have observed merging of our two atom clouds. (1) and (2) show the individual clouds before merging and (3) shows the resulting merged cloud.
Theoretical simulation of merging two 85Rb quadrupole traps
May 2010
Theoretical simulation of the merging of two quadrupole potentials in an experiment using 85Rb atoms suggests that the ratio of the gradients of the two pairs of coils must be adjusted during the merging process to ensure both atom clouds remain. Figure (a) gives a map of the relevant parameter space for merging. The colour map indicates the depth of a particular trap containing one cloud of atoms (see (c) for region I and (e) for region II), effectively indicating where merging can begin to occur. The dashed line in (a) shows the theoretical ideal ramp for maintaining atoms during the merging process. We need to enter region III through region I to ensure minimal heating and loss of atoms. We use a basic 1D model to predict an ideal path. Now we just need to wait and see if the experiment fits the theory!
Steve in Greece!
April 2010
Steve has visited the FOMO 2010 conference, representing the soliton project. An abstract for our project in relation to this conference can be found on the FOMO website.
First observation of 85Rb in a single beam dipole trap
April 2010
We have now observed the trapping of 85Rb in our single beam dipole trap. In the image the trapped atoms can be seen as an asymmetric shape at the top, due to reduced trapping in the axial direction as we use a magnetic field to trap along this axis. Atoms that weren't caught by the dipole trap can be seen falling to the bottom of the glass cell.
Radio-frequency evaporation of 85Rb
March 2010
Using radio-frequency evaporation we have cooled our 85Rb atoms down to a temperature of 30µK. At each stage we halve the temperature of the atomic cloud, starting at 250µK.
Transport Optimisation
February 2010
We have optimised the process of transporting our atoms from the MOT chamber to the science cell (see images of September 2008). This has ensured that minimal heating occurs during transport, resulting in an atomic cloud with a temperature of 250µK containing 6x108 85Rb atoms.
New LabVIEW control system
January 2010
This month we have seen the culmination of the development of a new control system for our experiment. Our software interface has changed, displaying an 'idealised timing diagram' to the user so that we know exactly what is running at a given time. The hardware we use is a National Instruments PCI-7833R FPGA card. The field programmable gate array (FPGA) allows us to reprogram the hardware after manufacture to adapt the card to our experiment.
Atoms transported towards the surface
November 2009
We're able to transport our atoms in the quadrupole trap down into the glass cell, where we're now can image the atoms using absorption imaging. To see the atoms getting closer to the surface, click here.
Going over the obstacle!
October 2009
This week we've been able to move the atoms over the obstacle in the transport path by applying a bias field and shifting the atoms over. On the left is shown a drawing of the obstacle mount, the prism itself sits in a macor support, which is embedded in a stainless steel mount. By varying the obstacle shift field, the atoms are able to pass over the obstacle, and there is a sharp cutoff as shown in the graph on the right.
First atom surface interactions observed!
October 2009
This week we've have been demonstrating magnetic transport in our vacuum system. The first graph shows the atoms travelling through the vacuum system, hitting two apertures where part of the cloud gets cut off and atom surface interaction when we hit the obstacle prism. The recapture value doesn't take into account the lifetime in the MT. In the following weeks we plan to optimise the magnetic transport, get the cloud central through both apertures and over the obstacle prism in order to be able to image the cloud in the science cell, using absorption imaging.
Thomas & Clemens complete their summer placement.
September 2009
Thomas Pichler and Clemens Streitberger, undergraduates from the University of Innsbruck, completed their nine week summer placement. Here they are shown working in the new lab on the characterisation of Faraday rotation signals in a hot atomic rubidium vapour. We plan to use such signals to lock the laser for degenerate Raman sideband cooling approximately 10GHz from the atomic resonance.
Magnetically trapped 85Rb atoms
August 2009
After implementing our computer control for the experimental apparatus, we're now able to magnetically trap atoms. The image shows the fluorescence signal for a MOT-Load, Magnetic-Trap and Recapture sequence. The MOT is loaded with a gradient of 10G/cm and then the atoms are transferred into a quadrupole trap, which is provided by the transport coils. The MT loads with 50G/cm and then the gradient is ramped up to prepare the atoms for the magnetic transport. We're able to recapture 40% of the atoms in the MOT so far.
Molasses stage of 85Rb atoms
August 2009
After trapping the atoms in a MOT and compressing them, a molasses stage is performed by switching of the magnetic field gradient and detuning of the trapping light. See a video of the molasses here.
Quantum reflection of bright matter-wave solitons
June 2009
Our proposal to use of bright matter-wave solitons to probe and study quantum reflection from a solid surface at normal incidence has now been published in Physica D 238, 1299-1305 (2009) - as part of a special issue connected to the conference on Nonlinear Phenomena in Degenerate Quantum Gases held in Toledo, Spain in April, 2008 We show to the right the schematic of the proposed experimental scenario where the soliton propagates along the 1D waveguide. Near the surface the atoms experience a potential resulting from the combination of the atom-surface potential and the light-shift associated with the evanescent field. Removing the evanescent field allows the study of quantum reflection from the purely attractive atom-surface potential.
In the same issue are study of bright solitary waves of trapped atomic Bose-Einstein condensates and the role of the relative phase in collisions was also published Physica D 238, 1456-1461 (2009)
MOT found in the new Vacuum system!
May 2009
The new vacuum system showed the first time a MOT during this week. In future work we're going to increase the beam size, which will hopefully provide lots of cold atoms in our MOT.
Construction of the vacuum system is completed!
April 2009
After much agonising the vacuum system is finally completed and positioned on the optical table - just in time for the laboratory tours at the EuroQUAM satellite meeting on "Cold and Ultracold Molecules" held in Durham where we also presented a poster on our plans for the apparatus.
Rb and Cs MOT during the last week
November 2008
Five months of hard work have been honored this week. We started with a Cs MOT on Wednesday, and finished the week with a Rb MOT. The laser setup of the Cs MOT was build on a portable board, which has been delivered to the University of Newcastle. Both magneto-optical traps were realised in a pyramid chamber.
 
Vacuum design complete
September 2008
The vacuum design for the soliton experiment has now been completed. Below are some 3D images of the setup, which can be enlarged if clicked. The coils are as follows: Red = Transport, Purple = MOT, Yellow = Obstacle avoidance (Bias), Pink = Science, Green = Bias 1 and Cyan = Bias 2. See a tour of the setup here.
 
Tim completes his summer studentship
September 2008
Tim Wiles, from Durham University, completed his 10 week summer studentship on the soliton project. For the first half of the studentship his focus was on the creation of a bias coil pair to allow magnetic transport around an obstacle. Matlab was used to model the magnetic fields and the path taken due to their interactions. An example movie, a still of which is shown on the right, can be seen here. In the second half his focus shifted towards Cesium spectroscopy, in preparation for a level 4 project that will be taken by a student this year. Tim has also shown an interest in 3D modelling using Blender and as a result has created a 3D version of the soliton setup. A movie of this can be seen here.
Pauline completes her summer internship
August 2008
Pauline Trouve from Institut d'Optique in Paris completed her 11 week summer internship on the soliton project. During her stay she worked on a number of topics, most notably, the modelling of the combined optical and magnetic potential for evaporative cooling and modelling of the atom-surface and evanescent wave potentials for the future study of quantum reflection. She has kindly left us with some well documented Matlab code! The graph to the right shows the combined potential in the vicinity of a fused silica prism that results from the sum of the evanescent wave and atom-surface potentials.
QuDeGPM - Collaborative Research Project is funded!
July 2008
ESF announce that our European Collaborative Research Project on "Quantum Degenerate Gases for Precision Measurements (QuDeGPM) is one of three projects funded under the EuroQUASAR programme. Led by Hanns-Christoph Nagerl (University of Innsbruck), the project involves seven other groups whose prinicpal investigators are Giovanni Modugno (CNR-INFM, Italy), Simon Cornish (Durham University), Claus Zimmermann (University of Tubingen), Philippe Bouyer (Institut d'Optique, Palaiseu, Paris), Jorg Schmiedmayer (Atominstitut Wien, Austria), Luis Santos (Leibniz Universitat Hannover, Germany) and Jacob Dunningham (University of Leeds, UK). The Durham component of this project is funded by EPSRC Grant EP/G026602/1.
The new research lab is ready!
June 2008
The new research lab is finished and ready to move in. At this point we'd like to thank all those people who contributed to the refurbishment of the room; with special thanks to Norman Thompson for overseeing the project, "Gez" Wathen for an excellent job on the canopies over the optical tables and John Dobson for numerous other little jobs including the water.
To all the other people who helped - THANKS!
Collisions of bright solitary matter waves
February 2008
Our theoretical study of the collisions of bright solitary matter waves is published in J. Phys. B 41, 045303 (2008). We show to the right (a) a density plot of a collision of two bright solitary waves with a relative phase of pi/2 which reveals a population transfer from one soliton to the other. In (b) we map out this population transfer as a function of the relative phase and velocity (different symbols). This result forms the basis for a new form of soliton interferometry.
Further details on our theoretical results can be found in the poster presented by Dr. Nick Parker at a recent conference in Toronto on Ultra-cold Nano-matter.
Bright solitary waves and trapped solutions for attractive BECs
July 2007
The first paper generated by our theory collaboration with Nick Parker and Andy Martin is published in J. Phys. B 40, 3127-3142 (2007). The figure to the right shows the evolution of the axial density of a BSW as the interaction parameter k is adiabatically increased past the critical point for collapse. Dark/light represents regions of high/low atomic density.
Bright matter-wave solitons: formation, dynamics and quantum reflection.
May 2007
EPSRC announce that our research proposal "Bright matter-wave solitons: formation, dynamics and quantum reflection" will be funded.
EPSRC Grant EP/F002068/1 will commence in January 2008.
Soliton formation results reported at conferences.
September 2006
SLC gives invited talks at Photon 06 and SoliQuantum '06 (Solitons and nonlinear phenomena in degenerate quantum gases). In a second talk at SoliQuantum '06 CSA presented the results of our theory activities and briefly mentioned our planned surface experiments. Both talks were received enthusiastically.
Formation of bright matter-wave solitons during the collapse of attractive Bose-Einstein condensates.
May 2006
The results of an experimental collaboration with Prof. C.E. Wieman at JILA, University of Colorado have been published (Phys. Rev. Lett. 96, 170401 (2006)). The plot on the left shows the ratio of the number of remnant condensate atoms to the critical number against the mean number of observed solitons. Each soliton clearly contains less than the critical number of atoms and is therefore expected to be stable.
Download a poster given on this work at ICAP 2006 in Innsbruck.