Backward evolving quantum states

  title={Backward evolving quantum states},
  author={Lev Vaidman},
  journal={Journal of Physics A},
  • L. Vaidman
  • Published 2007
  • Physics
  • Journal of Physics A
The basic concept of the two-state vector formalism, which is the time symmetric approach to quantum mechanics, is the backward evolving quantum state. However, due to the time asymmetry of the memory's arrow of time, the possible ways to manipulate a backward evolving quantum state differ from those for a standard, forward evolving quantum state. The similarities and the differences between forward and backward evolving quantum states regarding the no-cloning theorem, nonlocal measurements and… Expand

Figures from this paper

Paper Mentions

Blog Post
Time Symmetry and the Many-Worlds Interpretation
An attempt to solve the collapse problem in the framework of a time-symmetric quantum formalism is reviewed. Although the proposal does not look very attractive, its concept - a world defined by twoExpand
The Two-State Vector Formalism: An Updated Review
The two-state vector formalism of quantum mechanics is a time-symmetrized approach to standard quantum theory particularly helpful for the analysis of experiments performed on preand post-selectedExpand
Quantum Instruments as a Foundation for Both States and Observables
We demonstrate that quantum instruments can provide a unified operational foundation for quantum theory. Since these instruments directly correspond to laboratory devices, this foundation provides anExpand
Retrocausality and Quantum Measurement
A retrocausal interpretation of quantum mechanics is examined and is applied to the problem of measuring an optical qubit before the qubit is actually created. Although the predictions of theExpand
Probability, Arrow of Time and Decoherence
This paper relates both to the metaphysics of probability and to the physics of time asymmetry. Using the formalism of decoherent histories, it investigates whether intuitions about intrinsic timeExpand
Weak value beyond conditional expectation value of the pointer readings
It is argued that a weak value of an observable is a robust property of a single pre- and postselected quantum system rather than a statistical property. During an infinitesimal time a system with aExpand
Valeurs Faibles, Trajectoires Faibles et Interferométrie
La theorie de la mesure, basee sur la mesure projective, constitue un aspect fondamental de la mecanique quantique. La mesure faible differe de la mesure projective traditionnelle sur laquelle lesExpand


Nonlocal Measurements in the Time-Symmetric Quantum Mechanics
Although for some nonlocal variables the standard quantum measurements which are reliable, instantaneous, and nondemolition, are impossible, demolition reliable instantaneous measurements of allExpand
Complete description of a quantum system at a given time
A generalization of the description of a quantum system in the time interval between two measurements is presented. A new concept of a generalized state is introduced. Generalized states yield aExpand
Properties of a quantum system during the time interval between two measurements.
  • Aharonov, Vaidman
  • Physics, Medicine
  • Physical review. A, Atomic, molecular, and optical physics
  • 1990
A description of quantum systems at the time interval between two successive measurements is presented, and how this approach leads to a new concept: a weak value of an observable. Expand
Two-time interpretation of quantum mechanics
We suggest an interpretation of quantum mechanics, inspired by the ideas of Aharonov et al. of a time-symmetric description of quantum theory. We show that a special final boundary condition for theExpand
Teleportation of quantum states.
  • Vaidman
  • Physics, Medicine
  • Physical review. A, Atomic, molecular, and optical physics
  • 1994
The recent result of Bennett of teleportation of an unknown quantum state is obtained in the framework of nonlocal measurements proposed by Aharonov and Albert, and the latter method is generalized to the teleportation of a quantum state of a system with continuous variables. Expand
A single quantum cannot be cloned
If a photon of definite polarization encounters an excited atom, there is typically some nonvanishing probability that the atom will emit a second photon by stimulated emission. Such a photon isExpand
Consistent histories and the interpretation of quantum mechanics
The usual formula for transition probabilities in nonrelativistic quantum mechanics is generalized to yield conditional probabilities for selected sequences of events at several different times,Expand
Teleporting an unknown quantum state via dual classical and Einstein-Podolsky-Rosen channels.
An unknown quantum state \ensuremath{\Vert}\ensuremath{\varphi}〉 can be disassembled into, then later reconstructed from, purely classical information and purely nonclassical Einstein-Podolsky-RosenExpand
Causality constraints on nonlocal quantum measurements.
  • Popescu, Vaidman
  • Physics, Medicine
  • Physical review. A, Atomic, molecular, and optical physics
  • 1994
It is proved that verification measurements of entangled states necessarily erase local information and it is shown that measurability of certain projection operators which play an important role in axiomatic quantum theory contradicts the causality principle. Expand
Quantum nonlocality without entanglement in a pair of qubits
We consider unambiguous discrimination of two separable bipartite states, one being pure and the other being a rank-2 mixed state. There is a gap between the optimal success probability under globalExpand