How long does it take to implement a projective measurement?
- URL: http://arxiv.org/abs/2011.13254v3
- Date: Wed, 16 Mar 2022 13:01:27 GMT
- Title: How long does it take to implement a projective measurement?
- Authors: Philipp Strasberg and Kavan Modi and Michalis Skotiniotis
- Abstract summary: We show that the implementation of a quantum measurement requires a minimum time.
This time scales proportionally with the diameter of the quantum mechanical object, on which the measured observable acts non-trivially.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: According to the Schr\"odinger equation, a closed quantum system evolves
continuously in time. If it is subject to a measurement however, its state
changes randomly and discontinuously, which is mathematically described by the
projection postulate. But how long does it take for this discontinuous change
to occur? Based on simple estimates, whose validity rests solely on the fact
that all fundamental forces in nature are finite-ranged, we show that the
implementation of a quantum measurement requires a minimum time. This time
scales proportionally with the diameter of the quantum mechanical object, on
which the measured observable acts non-trivially, with the proportionality
constant being around $10^{-5}$ s/m. We confirm our bound by comparison with
experimentally reported measurement times for different platforms. We give a
pedagogical exposition of our argumentation introducing along the way modern
concepts such as ancilla-based measurements, the quantum speed limit, and
Lieb-Robinson velocity bounds.
Related papers
- Time evolution in quantum mechanics with a minimal time scale [0.0]
We show a quantum theory exhibiting a minimum measurable time scale.
We use the Page-Wootters formalism to describe time evolution of a quantum system.
A minimal time scale allows also to introduce a discrete Schrodinger equation describing time evolution on a lattice.
arXiv Detail & Related papers (2024-10-23T17:11:50Z) - Effect of measurements on quantum speed limit [0.0]
We show that under continuous measurement, the speed of transportation of a quantum system tends to zero.
For small time scale, there is an enhancement of quantum speed even if the measurement strength is finite.
Our findings can have applications in quantum computing and quantum control where dynamics is governed by both unitary and measurement processes.
arXiv Detail & Related papers (2024-06-13T11:14:22Z) - Measurement events relative to temporal quantum reference frames [44.99833362998488]
We compare two consistent approaches to the Page-Wootters formalism to clarify the operational meaning of evolution and measurements.
We show that for non-ideal clocks, the purified measurement approach yields time non-local, non-unitary evolution.
arXiv Detail & Related papers (2023-08-21T18:26:12Z) - Quantifying measurement-induced quantum-to-classical crossover using an
open-system entanglement measure [49.1574468325115]
We study the entanglement of a single particle under continuous measurements.
We find that the entanglement at intermediate time scales shows the same qualitative behavior as a function of the measurement strength.
arXiv Detail & Related papers (2023-04-06T09:45:11Z) - Time dispersion in quantum electrodynamics [0.0]
Quantum electrodynamics is often formulated in a way that appears fully relativistic.
We show that entanglement in time has the welcome side effect of eliminating the ultraviolet divergences.
With recent developments in attosecond physics and in quantum computing, these effects should now be visible.
arXiv Detail & Related papers (2022-11-01T00:42:28Z) - Bounding the Minimum Time of a Quantum Measurement [1.534667887016089]
We derive lower bounds on the time needed for a measurement to occur.
Our bound scales proportionally to the change in entropy of the measured system.
We evaluate our bound in two examples where the environment is modelled by bosonic modes and the measurement apparatus is modelled by spins or bosons.
arXiv Detail & Related papers (2022-09-13T18:08:51Z) - Heisenberg-Limited Waveform Estimation with Solid-State Spins in Diamond [15.419555338671772]
Heisenberg limit in arbitrary waveform estimation is quite different with parameter estimation.
It is still a non-trivial challenge to generate a large number of exotic quantum entangled states to achieve this quantum limit.
This work provides an essential step towards realizing quantum-enhanced structure recognition in a continuous space and time.
arXiv Detail & Related papers (2021-05-13T01:52:18Z) - Does the Heisenberg uncertainty principle apply along the time
dimension? [0.0]
Heisenberg uncertainty principle (HUP) applies along the time dimension in the same way it applies along the three space dimensions.
Re Relativity says it should; current practice says no.
With recent advances in measurement at the attosecond scale it is now possible to decide this question experimentally.
arXiv Detail & Related papers (2021-01-26T01:36:08Z) - The Time-Evolution of States in Quantum Mechanics [77.34726150561087]
It is argued that the Schr"odinger equation does not yield a correct description of the quantum-mechanical time evolution of states of isolated (open) systems featuring events.
A precise general law for the time evolution of states replacing the Schr"odinger equation is formulated within the so-called ETH-Approach to Quantum Mechanics.
arXiv Detail & Related papers (2021-01-04T16:09:10Z) - Entropic Uncertainty Relations and the Quantum-to-Classical transition [77.34726150561087]
We aim to shed some light on the quantum-to-classical transition as seen through the analysis of uncertainty relations.
We employ entropic uncertainty relations to show that it is only by the inclusion of imprecision in our model of macroscopic measurements that we can prepare a system with two simultaneously well-defined quantities.
arXiv Detail & Related papers (2020-03-04T14:01:17Z) - Projection evolution and quantum spacetime [68.8204255655161]
We discuss the problem of time in quantum mechanics.
An idea of construction of a quantum spacetime as a special set of the allowed states is presented.
An example of a structureless quantum Minkowski-like spacetime is also considered.
arXiv Detail & Related papers (2019-10-24T14:54:11Z)
This list is automatically generated from the titles and abstracts of the papers in this site.
This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.