REVIEW
One-dimensional completed scattering and quantum nonlocality of entangled states
Quantum Physics · Submitted 21 Feb 2006 · 69 references
Pith's verdict: A real but conditional subensemble dwell-time calculation for symmetric barriers is sold as a general resolution of tunneling times and nonlocality; referee-worthy as a limited model, but the headline claims outrun the proof.
T0 · AI review
Why Pith says this
Highlight any text to comment on it.
Referee report
The paper
The paper claims
A new decomposition of one-dimensional scattering wave functions into transmitted and reflected subensembles is used to argue that dwell time, not group time, is the true tunneling time and that the Hartman effect is an artifact.
The reading
This paper proposes a different picture. It divides the single scattering process into two alternative subprocesses, one for particles that will be transmitted and one for particles that will be reflected, and it constructs a separate wave packet for each. For a symmetric barrier, the reflected packet is chosen to vanish at the midpoint, so reflected particles never cross into the far half of the barrier. The transmitted packet carries probability through the whole barrier. The author then uses a Larmor clock, a tiny magnetic field that makes the particle's spin precess while it is inside the barrier, to argue that the measured time for each subensemble is the dwell time computed from its own packet. For a thick rectangular barrier, the transmitted dwell time grows exponentially with width, so the Hartman effect disappears. The paper also claims that the group time measured in photonic experiments is not a real time and that quantum nonlocality in entangled states comes from treating a particle as if it could be in two places at once.
The paper is purely analytical. It reports no experiment, and its conclusions depend on changing a basic rule of quantum mechanics: that superposition of macroscopically distinct alternatives should not be averaged as a single process.
Extended reading notes
Core claim
The central claim is that a one-dimensional completed scattering is not a single one-way process but an entanglement of two alternative subprocesses, transmission and reflection, and that 'the wave function for the whole ensemble of scattering particles can be uniquely presented as the sum of two isometrically evolved wave packets to describe the (to-be-)transmitted and (to-be-)reflected subensembles of particles at all stages of scattering' (Abstract). A further load-bearing assertion is that a Larmor-clock timing procedure 'shows that namely the dwell time gives the time spent, on the average, by a particle in the barrier region, and it denies the Hartman effect' (Abstract). If correct, the standard scattering model, the group-time interpretation, and the reality of the Hartman effect are all wrong.
Load-bearing premise
The construction assumes that for a general potential barrier there exists a spatial point x_c (for a symmetric barrier, the midpoint) at which the reflected subensemble wave function vanishes identically for all wave numbers, so that no reflected probability crosses to the far side. The paper explicitly restricts the derivation to symmetric barriers in Section 3.2 ('we will further restrict ourselves by symmetric potential barriers') and then asserts without proof that 'the above analysis is valid in the general case.' If no such nodal separation point exists for asymmetric barriers, the unique decomposition, the separate dwell times, and the denial of the Hartman effect do not generalize. The corpuscular indivisibility postulate (Section 1) is a second load-bearing assumption, but the nodal-point existence is the more concrete technical premise.
Original abstract
Entanglement is usually associated with compound systems. We first show that a one-dimensional (1D) completed scattering of a particle on a static potential barrier represents an entanglement of two alternative one-particle sub-processes, transmission and reflection, macroscopically distinct at the final stage of scattering. The wave function for the whole ensemble of scattering particles can be uniquely presented as the sum of two isometrically evolved wave packets to describe the (to-be-)transmitted and (to-be-)reflected subensembles of particles at all stages of scattering. A noninvasive Larmor-clock timing procedure adapted to either subensemble shows that namely the dwell time gives the time spent, on the average, by a particle in the barrier region, and it denies the Hartman effect. As regards the group time, it cannot be measured and hence it cannot be accepted as a measure of the tunneling time. We argue that nonlocality of entangled states appears in quantum mechanics due to inconsistency of its superposition principle with the corpuscular properties of a particle. For example, this principle associates a 1D completed scattering with a single (one-way) process, while a particle, as an indivisible object, cannot take part in transmission and reflection, simultaneously.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
Entanglement is usually associated with compound systems. We first show that a one-dimensional (1D) completed scattering of a particle on a static potential barrier represents an entanglement of two alternative one-particle sub-processes, transmission and reflection, macroscopically distinct at the final stage of scattering. The wave function for the whole ensemble of scattering particles can be uniquely presented as the sum of two isometrically evolved wave packets to describe the (to-be-)transmitted and (to-be-)reflected subensembles of particles at all stages of scattering. A noninvasive Larmor-clock timing procedure adapted to either subensemble shows that namely the dwell time gives the time spent, on the average, by a particle in the barrier region, and it denies the Hartman effect. As regards the group time, it cannot be measured and hence it cannot be accepted as a measure of the tunneling time. We argue that nonlocality of entangled states appears in quantum mechanics due to inconsistency of its superposition principle with the corpuscular properties of a particle. For example, this principle associates a 1D completed scattering with a single (one-way) process, while a particle, as an indivisible object, cannot take part in transmission and reflection, simultaneously.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | Entanglement is usually associated with compound systems. | background 1.00 | 0.03 | 0.02 | asserted 0.96 |
| s1 | We first show that a one-dimensional (1D) completed scattering of a particle on a static potential barrier represents an entanglement of two alternative one-particle sub-processes, transmission and reflection, macroscopically distinct at the final stage of scattering. | contribution 0.69 | 0.92 | 0.37 | asserted 1.00 |
| s2 | The wave function for the whole ensemble of scattering particles can be uniquely presented as the sum of two isometrically evolved wave packets to describe the (to-be-)transmitted and (to-be-)reflected subensembles of particles at all stages of scattering. | contribution 0.40 | 0.82 | 0.10 | asserted 1.00 |
| s3 | A noninvasive Larmor-clock timing procedure adapted to either subensemble shows that namely the dwell time gives the time spent, on the average, by a particle in the barrier region, and it denies the Hartman effect. | result 0.93 | 0.80 | 0.12 | asserted 1.00 |
| s4 | As regards the group time, it cannot be measured and hence it cannot be accepted as a measure of the tunneling time. | result 0.76 | 0.51 | 0.09 | asserted 1.00 |
| s5 | We argue that nonlocality of entangled states appears in quantum mechanics due to inconsistency of its superposition principle with the corpuscular properties of a particle. | interpretation 0.98 | 0.41 | 0.51 | asserted 0.83 |
| s6 | For example, this principle associates a 1D completed scattering with a single (one-way) process, while a particle, as an indivisible object, cannot take part in transmission and reflection, simultaneously. | interpretation 1.00 | 0.21 | 0.20 | asserted 0.99 |
What was examined, and what was not
- arXiv listing abstract v4
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
References
How the literature uses it
Papers whose main result relates to this one's
States the same result 1 paper
-
Quantum nonlocality appears in this problem due to the inconsistency of the superposition principle with the corpuscular properties of a particle.
New Model of One-dimensional Completed Scattering and the Problem of Quantum Nonlocality · 0.99
Discussion
Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.