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Measurement of the time spent by a tunnelling atom within the barrier region

Ramón Ramos, David Spierings, Isabelle Racicot +1 more

NatureJul 22, 2020186 citations

Tunneling Through a Squeezing Barrier: A Comment on the Barrier Traversal Time

Shin Takagi

JJAP seriesMay 31, 19931 citation

A traversal time for tunneling particles through a potential barrier

Chun-Fang Li, Qi Wang

Physica B Condensed MatterJan 1, 200110 citations

Traversal time for tunneling

Μ. Büttiker, Rolf W. Landauer

Advances in Solid State PhysicsSep 10, 200712 citations

Larmor precession and the traversal time for tunneling

Μ. Büttiker

Baz' and Rybachenko have proposed the use of the Larmor precession as a clock to measure the time it takes a particle to traverse a barrier. An applied magnetic field is confined to the barrier. The spin of the incident particles is polarized perpendicular to this field. The extent of the Larmor precession occurring during transmission is used as a measurement of the time spent traversing the barrier. However, the particles tunneling through an opaque barrier also acquire a spin component parallel to the field since particles with spin parallel to the field have a higher transmission probability than particles with spin antiparallel to the field. Similar effects are actually used to polarize electrons and neutrons. An interpretation of this experiment compares the results with an approach which determines the traversal time by studying transmission of particles through a time-modulated barrier. This leads to three characteristic times describing the interaction of particles with a barrier. A dwell time measures the average time interval during which a particle interacts with the barrier whether it is reflected or transmitted at the end of its stay, a traversal time measures the time interval during which a particle interacts with the barrier if it is finally transmitted, and a reflection time measures the interaction time of a reflected particle.Baz' and Rybachenko have proposed the use of the Larmor precession as a clock to measure the time it takes a particle to traverse a barrier. An applied magnetic field is confined to the barrier. The spin of the incident particles is polarized perpendicular to this field. The extent of the Larmor precession occurring during transmission is used as a measurement of the time spent traversing the barrier. However, the particles tunneling through an opaque barrier also acquire a spin component parallel to the field since particles with spin parallel to the field have a higher transmission probability than particles with spin antiparallel to the field. Similar effects are actually used to polarize electrons and neutrons. An interpretation of this experiment compares the results with an approach which determines the traversal time by studying transmission of particles through a time-modulated barrier. This leads to three characteristic times describing the interaction of particles with a barrier. A dwell time measures the average time interval during which a particle interacts with the barrier whether it is reflected or transmitted at the end of its stay, a traversal time measures the time interval during which a particle interacts with the barrier if it is finally transmitted, and a reflection time measures the interaction time of a reflected particle.

Physical review. B, Condensed matterMay 15, 1983699 citations

Traversal-Time Distribution and the Uncertainty Principle in Quantum Tunneling

H. A. Fertig

We derive the exact distribution of times spent in the classically forbidden region by a particle as it tunnels through a square barrier potential. We find that the integrated distribution has a simple interpretation. If one restricts the time spent in the barrier to be \ensuremath{\leqslant}\ensuremath{\tau}, then an effective uncertainty \ensuremath{\Delta}V is introduced in the barrier height, such that\ensuremath{\Delta}V\ensuremath{\tau}\ensuremath{\simeq}1. This uncertainty leads to unusual interference effects in the distribution. These interference effects explain why the average speed of a particle traversing a very opaque barrier may exceed the speed of light. \textcopyright{} 1990 The American Physical SocietyWe derive the exact distribution of times spent in the classically forbidden region by a particle as it tunnels through a square barrier potential. We find that the integrated distribution has a simple interpretation. If one restricts the time spent in the barrier to be \ensuremath{\leqslant}\ensuremath{\tau}, then an effective uncertainty \ensuremath{\Delta}V is introduced in the barrier height, such that\ensuremath{\Delta}V\ensuremath{\tau}\ensuremath{\simeq}1. This uncertainty leads to unusual interference effects in the distribution. These interference effects explain why the average speed of a particle traversing a very opaque barrier may exceed the speed of light. \textcopyright{} 1990 The American Physical Society

Physical Review LettersNov 5, 1990123 citations

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