When a tiny, quantum-scale, hypothetical balloon is popped in a vacuum, do the particles inside spread out all over the place as predicted by classical mechanics"
The question is deceptively complex, since quantum particles do not look or act like air molecules in a real balloon. Matter at the infinitesimally small quantum scale is both a wave and a particle, and its location cannot be fixed precisely because measurement alters the system.
Now, theoretical physicists at the University of Southern California and the University of Massachusetts Boston have proven a long-standing hypothesis that quantum-scale chaos exists … sort of.
Writing in the April 17 edition of Nature, senior author Maxim Olshanii reported that when an observer attempts to measure the energies of particles coming out of a quantum balloon, the interference caused by the attempt throws the system into a final, “relaxed” state analogous to the chaotic scattering of air molecules.
The result is the same for any starting arrangement of particles, Olshanii added, since the act of measuring wipes out the differences between varying initial states.
“It’s enough to know the properties of a single stationary state of definite energy of the system to predict the properties of the thermal equilibrium (the end state),” Olshanii said.
The measurement – which must involve interaction between observer and observed, such as light traveling between the two – disrupts the “coherent” state of the system, Olshanii said.
In mathematical terms, the resulting interference reveals the final state, which had been hidden in the equations describing the initial state of the system.
“The thermal equilibrium is already encoded in an initial state,” Olshanii said. “You can see some signatures for the future equilibrium. They were already there but more masked by quantum coherences.”
The finding holds implications for the emerging fields of quantum computing and quantum information theory, said Paolo Zanardi, an associate professor of physics studying quantum information at USC.
In Zanardi’s world, researchers want to prevent coherent systems from falling into the chaos of thermal equilibrium.
“Finding such ‘unthermalizable’ states of matter and manipulating them is exactly one of those things that quantum information/computation folks like me would love to do,” Zanardi wrote. “Such states would be immune from ‘decoherence’ (loss of quantum coherence induced by the coupling with environment) that’s still the most serious, both conceptually and practically, obstacle between us and viable quantum information processing.”
Zanardi and a collaborator introduced the notion of “decoherence-free” quantum states in 1997. Researchers such as Zanardi and Daniel Lidar, associate professor of chemistry, among others, have helped make USC a major center for the study of quantum computing.
Carl Marziali | EurekAlert!
Long-lived storage of a photonic qubit for worldwide teleportation
12.12.2017 | Max-Planck-Institut für Quantenoptik
Telescopes team up to study giant galaxy
12.12.2017 | International Centre for Radio Astronomy Research
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
12.12.2017 | Physics and Astronomy
12.12.2017 | Earth Sciences
12.12.2017 | Power and Electrical Engineering