Exotic Phenomena in Superfluid 3He at Ultralow Temperatures
Lead Research Organisation:
Lancaster University
Department Name: Physics
Abstract
Superfluid 3He is the most exotic liquid in existence. It only exists below a few thousandths of a degree above absolute zero. It owes its existence entirely to quantum mechanics and is therefore interesting to study to promote the better understanding of quantum systems in general. While it is superfluid and may flow without friction, the fact that it also has an associated spin 'superfluid' and an orbital angular momentum 'superfluid' gives it many unique properties, many of which remain to be discovered. Our group has pioneered the study of ballistic heat transport in superfluid 3He. Heat in the superfluid is carried by quasiparticle excitations. At very low temperatures these are so few as to hardly ever scatter. We can thus generate beams of ballistic quasiparticles and fire them at various obstacles formed by the superfluid itself. We have so far mastered the techniques for observing the Andreev reflection of such beams (a form of reflection unique to superfluids and superconductors). We now wish to develop the methods needed to measure the transmission of quasiparticle beams.We will use this technique to investigate the decay of quantum turbulence. In superfluid 3He turbulence takes the form of a tangle of identical quantised vortex lines. This is much simpler than classical turbulence which has eddies/vortices of variable sizes. The study of superfluid turbulence will give us a better understanding of turbulence in general. With quasiparticle transmission techniques we hope to obtain more quantitative information on the turbulence decay mechanisms in the zero-temperature limit where the dissipation mechanism should be determined by quantum effects rather than by conventional viscosity. We will also investigate the superfluid phase diagram of dirty 3He. Impurities may be effectively added to liquid 3He by confining it in aerogel, a nanoscale network of silica strands. Since pure 3He is so well understood, it is the ideal substance for investigating such effects. We will study how impurities influence the various superfluid phases and the transitions between them. Gapless superfluidity is an exotic phenomenon common in dirty superconductors where the binding energy of the constituent pairs providing the superfluid behaviour vanishes. We have recently seen this behaviour in the thermal conductivity of superfluid. With similar techniques we plan to study the cross-over from gapless to (the usual) gapped superfluidity. Further, where the superfluid transition in aerogel occurs at zero temperature, this constitutes a quantum phase transition dominated by quantum effects. This seems to be the cleanest such transition known and we are well placed to investigate the associated quantum fluctuations.The superfluid orbital properties of 3He are not evident at the temperatures available to most research groups. Our novel techniques allow us the lowest achievable temperatures where orbital superfluidity becomes apparent. We have indirect evidence of orbital superfluidity from exotic NMR signals from persistent precessing domains (PPDs). These are ultra long lived domains of coherent spin precession which have laser-like properties. By looking at the interaction of two PPDs we hope to gain more direct evidence of orbital superfluidity.Finally we plan to demonstrate an exotic mechanism unique to superfluid 3He affecting the motion of an object in the liquid. At absolute zero there are no excitations and an object should move freely through the superfluid as through a vacuum. However, if the object is heated, the thermal emission of quasiparticles should damp its motion. We will investigate this by moving a heated aerogel sample through the superfluid.We emphasise that most of the proposed experiments are only feasible at the very lowest temperatures made possible by our unique cooling techniques.
Organisations
- Lancaster University (Lead Research Organisation)
- Leiden University (Collaboration)
- Heidelberg University (Collaboration)
- NEEL Institute (Collaboration)
- Royal Holloway, University of London (Collaboration)
- Slovak Academy of Sciences (Collaboration)
- University of Ottawa (Collaboration)
- BlueFors Cryogenics (Collaboration)
- Aalto University (Collaboration)
- European Organization for Nuclear Research (CERN) (Collaboration)
- Physikalisch-Technische Bundesanstalt (Collaboration)
Publications
Bradley D
(2011)
A New Device for Studying Low or Zero Frequency Mechanical Motion at Very Low Temperatures
in Journal of Low Temperature Physics
Bradley DI
(2008)
Annihilation of an AB/BA interface pair in superfluid helium-3 as a simulation of cosmological brane interaction.
in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences
Bradley DI
(2007)
Contrasting mechanical anisotropies of the superfluid 3He phases in aerogel.
in Physical review letters
Bradley D
(2012)
Crossover from hydrodynamic to acoustic drag on quartz tuning forks in normal and superfluid 4 He
in Physical Review B
Fisher S
(2012)
Decay of persistent precessing domains in 3 He- B at very low temperatures
in Physical Review B
Bradley D
(2011)
Direct measurement of the energy dissipated by quantum turbulence
in Nature Physics
Fujiyama S
(2010)
Generation, evolution, and decay of pure quantum turbulence: A full Biot-Savart simulation
in Physical Review B
Bradley D
(2010)
History Dependence of Turbulence Generated by a Vibrating Wire in Superfluid 4He at 1.5 K
in Journal of Low Temperature Physics
Bradley D
(2007)
Magnetic Distortion of the B-like Phase of Superfluid 3He Confined in Aerogel
in Journal of Low Temperature Physics
Bradley D
(2010)
Measuring the Prong Velocity of Quartz Tuning Forks Used to Probe Quantum Fluids
in Journal of Low Temperature Physics
Bradley D
(2008)
Probing Andreev Reflection in Superfluid 3He-B Using a Quartz Tuning Fork
in Journal of Low Temperature Physics
Fisher S
(2009)
Quantum Turbulence
Bradley D
(2007)
Relic topological defects from brane annihilation simulated in superfluid 3He
in Nature Physics
Bradley D
(2007)
The AB Interface in Superfluid 3He as a Simulated Cosmological Brane
in Journal of Low Temperature Physics
Bradley D
(2009)
The Damping of a Quartz Tuning Fork in Superfluid 3He-B at Low Temperatures
in Journal of Low Temperature Physics
Bradley D
(2009)
The Transition to Turbulent Drag for a Cylinder Oscillating in Superfluid 4He: A Comparison of Quantum and Classical Behavior
in Journal of Low Temperature Physics
Bradley D
(2009)
Transition to Turbulence for a Quartz Tuning Fork in Superfluid 4He
in Journal of Low Temperature Physics
Bradley D
(2012)
Turbulent drag on a low-frequency vibrating grid in superfluid 4 He at very low temperatures
in Physical Review B
Description | We have made much progress in understanding how to image turbulence in quantum fluid systems which is much simpler than the classical phenomenon. We have designed a new imaging spectrometer which has the ability to detect and image the presence and evolution of a tangle of quantum vortices at the very lowest attainable temperatures (~ 100 microkelvin). A key general finding is that these experiments have demonstrated that we can reach and make experiments in the condensate in the unique temperature region where there are virtually no excitations. This is an exciting new area opening up and we are currently the World leaders in these studies. |
Exploitation Route | The knowledge gained will help others to be able to work in the 100 microkelvin regime in superfluid 3He where there is a wealth of new phenomena in the "pure condensate" regime waiting to be accessed. |
Sectors | Aerospace Defence and Marine Education Manufacturing including Industrial Biotechology Other |
Description | The work here feeds into UK industry's long-term planning for microkelvin experiments as a large fraction of the Worlds manufacturing in the area is situated in the UK. |
First Year Of Impact | 2016 |
Sector | Manufacturing, including Industrial Biotechology |
Impact Types | Economic |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | Aalto University |
Department | Department of Applied Physics |
Country | Finland |
Sector | Academic/University |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | BlueFors Cryogenics |
Country | Finland |
Sector | Private |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | European Organization for Nuclear Research (CERN) |
Department | Physics Department |
Country | Switzerland |
Sector | Academic/University |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | Heidelberg University |
Department | Department of Physics and Astronomy |
Country | Germany |
Sector | Academic/University |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | Leiden University |
Department | Leiden Institute of Physics |
Country | Netherlands |
Sector | Academic/University |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | NEEL Institute |
Country | France |
Sector | Public |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | Physikalisch-Technische Bundesanstalt |
Country | Germany |
Sector | Academic/University |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | Royal Holloway, University of London |
Department | Department of Physics |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | Slovak Academy of Sciences |
Department | Institute of Experimental Physics SAS |
Country | Slovakia |
Sector | Academic/University |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |
Description | EU FP7 Infrastructure Project MICROKELVIN 2009-2014 |
Organisation | University of Ottawa |
Department | Department of Physics |
Country | Canada |
Sector | Academic/University |
PI Contribution | This was an FP7 Infrastructure Network, where Lancaster was one of the three access-giving hubs. Thus we played a senior role in the consortium with GRP acting as chairman of the governing council. |
Collaborator Contribution | We undertook joint research projects with the other partners and provided experimental access to our facilities (paid for by FP7) for partnmers and others to run experiments at Lancaster. |
Impact | Many publications already listed under EPSRC grants. |
Start Year | 2009 |