From: mk_thisisit
The field of ultracold atoms is crucial for understanding and developing quantum technologies [00:00:08]. This area of physics focuses on manipulating individual atoms and molecules at extremely low temperatures, where quantum effects become observable [00:05:30].
Ultracold Environments
Laboratories in places like Warsaw and CERN are home to the coldest and hottest places in the universe, respectively [00:00:02], [00:00:25]. The temperatures achieved with cold atoms are de facto a billion times less than room temperature [00:00:26], approaching absolute zero [00:10:06]. While true absolute zero cannot be reached, systems can be cooled arbitrarily close to it [00:11:02]. If no alien civilizations exist, then experiments with cold atoms in laboratories on Earth, including those in Warsaw, host the coldest places in the universe [00:11:52].
At these extremely low temperatures, atoms move incredibly slowly, nearing the minimum possible energy they can possess [00:08:38], [00:08:42]. Temperature itself is a measure of the energy atoms and molecules have, reflecting their average speed and movement [00:03:33], [00:03:43].
Manipulating Single Atoms and Ions
Recent advancements in physics have made it possible to manipulate individual atoms, which is considered an incredible achievement given their vast numbers [00:05:30], [00:05:43]. A significant achievement involved cooling a single ion to temperatures close to one micro Kelvin—a record low for an ion [00:05:22], [00:07:27], [00:07:34]. This was accomplished by immersing a single ion, caught in a complex trap, into a gas of very cold atoms and cooling it through collisions [00:06:04], [00:06:14].
Methods for trapping and manipulating atoms include:
- Vacuum Chambers: Experimental systems are isolated in high-quality vacuum chambers to prevent outside interference [00:21:49].
- Magnetic Fields: Atoms can be caught in suitably shaped magnetic fields that create a “trap” [00:22:38].
- Optical Tweezers/Light Crystals: Laser beams can be used to generate vapor of atoms and then catch them [00:21:16], [00:22:16]. This involves the intersection of two or three laser beams, creating areas of high light intensity where atoms can be trapped [00:31:07], [00:31:11], [00:31:15].
- Ionization: For ions, it is simpler: a single atom can be ionized and then caught [00:23:26].
It is even possible to photograph a single atom by collecting the light reflected from it, similar to how a camera captures an image [00:23:35], [00:23:51].
Quantum Phenomena at Ultralow Temperatures
At ultracold temperatures, quantum effects become visible, as atoms move so slowly that their energy levels become quantized and discrete [00:09:03], [00:09:10]. This “discreteness” of energy levels allows for novel phenomena [00:09:19].
- Quantum Superposition: With single ions, it is “very, very easy” to create a Schrödinger’s cat state, where an ion can exist simultaneously in multiple places or states [00:13:03], [00:13:08], [00:24:26]. This can be observed by repeating experiments many times, revealing the probability distribution given by the wave function [00:24:33], [00:24:48].
- Control of Chemical Reactions: At extremely low temperatures, external factors like magnetic fields can drastically influence the speed of chemical reactions, accelerating or slowing them down by a million times [00:13:53], [00:13:59]. This provides a deep, quantum-level understanding of chemical synthesis [00:28:38].
- Quantum Teleportation of Chemical Reactions: Researchers contemplate the theoretical possibility of teleporting a chemical reaction, where a reaction happening with one ion could formally be considered to have occurred with a distant ion through a teleportation protocol [00:14:21], [00:14:38].
These studies allow for precise investigations into the fundamental laws of nature, complementary to high-energy physics experiments like CERN [00:15:04], [00:15:17]. By eliminating thermal noise at low temperatures, measurements of atomic and molecular structures can be made with much higher accuracy [00:15:24], [00:15:49].
Quantum Computing Technologies and Cold Atoms
The development of quantum computer technology based on cold atoms is currently experiencing a “renaissance” [00:40:43], [00:40:47]. While cold ions have always been considered for quantum computers, neutral cold atoms were previously a “Cinderella” technology [00:40:54], [00:40:57]. However, in the last five years, advancements in technologies utilizing cold atoms in optical networks (light crystals) and optical tweezers have shown the potential to surpass other quantum computing technologies [00:41:06], [00:41:16]. This technology is being actively developed by groups at Harvard and in France, among others, demonstrating rapid progress [00:41:26], [00:41:28], [00:41:32]. This new class of quantum computers is being built on the basis of cold atoms in optical networks, employing techniques like Rydberg excitations [00:42:04], [00:42:06], [00:42:10], [00:42:14].
Broader Implications
Beyond quantum computing, research with cold atoms has implications for fundamental physics:
- Dark Matter Detection: There are attempts to use cold atoms and highly accurate atomic clocks (based on ultracold atoms) to detect dark matter [00:35:05], [00:35:25], [00:35:36]. This relies on the hypothesis that dark matter might have a domain structure that moves through the universe [00:35:42], [00:35:46].
- Electron Dipole Moment: Ultracold molecules are used to measure the electron dipole moment [00:16:01], [00:16:04]. A non-zero measurement would indicate a breach in the standard model of particle physics [00:17:08]. Measurements so far have consistently shown zero, but future findings could significantly challenge current understanding [00:16:59], [00:17:29]. This research connects the manipulation of atoms to fundamental questions in elementary particle physics [00:17:49].