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more expanded like waves. The cooler they are, the larger is their expansion and soon all atoms are overlapping each other. Despite it being a gas of atoms, none of them can be distinguished separately inside this blob of gas and they all have the same energy. Whatever behaviour we see now becomes a collective property of this blob. In scientific community we call the blob a ‘condensation’. Particles which can undergo such condensation are ‘bosons.’ So far, we understand, the condensation of bosonic particles can behave like a quantum droplet under certain conditions. What are they?
“Strongly dipolar bosonic gases in ultracold temperature can form quantum droplets.”
Unlike the water molecules in the classical gas, one would assume the gas atoms do not like to remain close because we know that they disperse. But in special
types of atoms such as Erbium
and Dysprosium, physicists
have managed to find strong
attractions between atoms. This
attraction stems from the nature
of some atoms to behave like
tiny magnets. Such atoms are
termed as dipolar atoms and a
gas of such atoms is a dipolar
gas. If this attraction is strong
enough it can pull the atoms
together against dispersion,
which may be caused by
other repulsive forces between
atoms, quantum fluctuations
due to slightly energetic atoms
and slow motion of the atoms in the gas.
There now, we have a quantum droplet of dipolar gas. The crucial factor is at ultralow temperature, the atoms are slow and less
Ms. Chinmayee Mishra || 277
energetic enough for the dipolar attraction to hold them together which would not have been possible in a classical gas with huge number of energetic atoms.
In our group as well as with collaborators from Germany, we have theoretically studied the properties of quantum droplets of dipolar bosonic gases. This novel phenomenon is a newly emerged breakthrough in the field of ultracold gases, discovered in the ultracold experimental lab in Stuttgart, Germany. One quirky detail regarding these droplets are that, unlike classical liquid droplets, they are not spherical. They are often elongated like a cylinder. It is because of the way the atoms attracteachotherisasymmetricinalldirection, just like how tiny magnets attract each other only one side. In our recent work, we showed how to change the droplets from cigar-shaped to pancake-shaped simply by tweaking the
way the atoms attract. That is right, we can control how atoms attract or repel by applying electric or magnetic fields, similar to how you can control magnets using magnetic fields.
Just when you think we know everything about the fundamentals of Physics, discoveries like these have surprised us to our core. It goes to remind us why to never stop questioning and to always rage against the darkness of ignorance.
Do not go gentle into that good
night,
Old age should burn and rave at close of day; Rage, rage against the dying of the light.
There now, we have a quantum droplet of dipolar gas. The crucial factor is at ultralow temperature, the atoms are slow and less energetic enough for the dipolar attraction to hold them together which would not have been possible in a classical gas with huge number of energetic atoms.