Quantum energy teleportation

Quantum energy teleportation,  a hypothesis first put forward  by Japanese physicist Masahiro Hotta of Tohoku University, proposes that it may be possible to teleport energy by exploiting quantum energy fluctuations of an entangled vacuum state of a quantum field.  The hypothesis proposes that energy may be injected into a zero-point fluctuation of the field at one place and extracted from a fluctuation at another place. Even for interstellar distance energy transfer, the amount of teleported energy is nonzero, but negligibly small. In contrast, the teleportation protocol will be effective in small quantum worlds of nanoscale devices like quantum computers.

The idea is a continuation of work by computer scientist Charles H. Bennett on quantum teleportation C.H. Bennett, et al. in 1993 and experimentally confirmed by various experiments in the following years. Protocols of the quantum teleportation transfer quantum information, but cannot teleport energy itself.

Description

Quantum energy teleportation is a quantum protocol which transfers locally available energy, in an operational sense, from one subsystem of a many-body system to another in an entangled ground state by using local operations and classical communication (LOCC). The locally available energy indicates the energy which can be extracted from a subsystem by local operations and harnessed for any purpose. The transfer speed can be much faster than the velocity of energy diffusion of the system. It does not allow energy transportation at superluminal (faster than light) speed, nor does it increase total energy itself contained in a distant place. Though zero-point energy of the ground state exists everywhere in the system and contributes to the amount of the total energy, it is not available by use of ordinary local operations. However, if information about a local zero-point fluctuation, which carries a portion of the zero-point energy, is obtained by a measurement of a distant subsystem via ground-state entanglement, the energy becomes available, and can be extracted by a local operation dependent on the information. The extraction of the energy is accompanied by generation of negative energy density, which is allowed in quantum physics of many-body systems including quantum fields, and retains the local energy conservation law. The remote measurement, which provides the information for energy extraction, injects energy into the measured subsystem. A portion of the injected energy, which amount is larger than that of the energy extracted from the zero-point fluctuation, becomes unavailable because of entanglement breaking by the measurement, and cannot be retrieved by local operations in the measurement region. Thus, during the protocol, the amount of locally available energy decreases in the measurement region, and it increases in the energy extraction region. The injected energy is the input of this teleportation protocol, and the extracted energy is the output.
 
The details can be found in a review article written by Hotta.

Experiments
Experimental verification of the teleportation has not been achieved yet. A realistic experimental proposal is provided using a semiconductor exhibiting the quantum Hall effect.

References

Category:Theoretical physics
Category:Quantum information science