scholarly journals Entropic Characterization of Quantum States with Maximal Evolution under Given Energy Constraints

Entropy ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 770 ◽  
Author(s):  
Ana P. Majtey ◽  
Andrea Valdés-Hernández ◽  
César G. Maglione ◽  
Angel R. Plastino
Keyword(s):  
Energy Distribution ◽  
Variational Problem ◽  
Quantum System ◽  
Dynamical Evolution ◽  
Quantum States ◽  
Time Interval ◽  
Expectation Value ◽  
Energy Constraints ◽  
Pure Quantum State

A measure D [ t 1 , t 2 ] for the amount of dynamical evolution exhibited by a quantum system during a time interval [ t 1 , t 2 ] is defined in terms of how distinguishable from each other are, on average, the states of the system at different times. We investigate some properties of the measure D showing that, for increasing values of the interval’s duration, the measure quickly reaches an asymptotic value given by the linear entropy of the energy distribution associated with the system’s (pure) quantum state. This leads to the formulation of an entropic variational problem characterizing the quantum states that exhibit the largest amount of dynamical evolution under energy constraints given by the expectation value of the energy.

The discovery and characterization of 2020 AV2, the first known asteroid in the class of inner-Venus asteroids

2021 ◽  
Author(s):  
Bryce T. Bolin ◽  
Wing-Huen Ip ◽  
Frank J. Masci ◽  
George Helou
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Dynamical Evolution ◽  
Small Population ◽  
Population Models ◽  
Spectral Energy ◽  
Expected Number ◽  
Optical Telescope ◽  
Spectroscopic Observations

<p>Near-Earth asteroid population models predict a small population of asteroids located entirely within the orbit of Venus. We report the discovery of the first inner-Venus asteroid (IVA), 2020 AV<sub>2</sub>, was first detected by the Zwicky Transient Facility (ZTF) on the Samuel Oschin Telescope 48-inch telescope at Palomar Observatory on 2020 January 4. Recovery observations by the Spectral Energy Distribution Machine on the Palomar 60-inch Telescope and the Lulin Optical Telescope at Lulin Observatory in late 2021 November greatly extended its orbit to ~330 days confirm its location inside the orbit of Venus and allowing for detail investigation of its dynamical evolution. In addition, a comparison with the NEO model reveals its likely source location in agreement with recent spectroscopic observations. In addition, we provide an estimate of our observational completeness for detecting inner-Venus asteroids with ZTF with implications on the expected number of their detection.</p>

scholarly journals The Underlying Order Induced by Orthogonality and the Quantum Speed Limit

2021 ◽  
Vol 3 (3) ◽  
pp. 376-388
Author(s):  
Francisco J. Sevilla ◽  
Andrea Valdés-Hernández ◽  
Alan J. Barrios
Keyword(s):  
Energy Spectrum ◽  
Energy Distribution ◽  
Finite Time ◽  
Complete Characterization ◽  
Comprehensive Analysis ◽  
Orthogonality Condition ◽  
Speed Limit ◽  
Physical Quantities

We perform a comprehensive analysis of the set of parameters {ri} that provide the energy distribution of pure qutrits that evolve towards a distinguishable state at a finite time τ, when evolving under an arbitrary and time-independent Hamiltonian. The orthogonality condition is exactly solved, revealing a non-trivial interrelation between τ and the energy spectrum and allowing the classification of {ri} into families organized in a 2-simplex, δ2. Furthermore, the states determined by {ri} are likewise analyzed according to their quantum-speed limit. Namely, we construct a map that distinguishes those ris in δ2 correspondent to states whose orthogonality time is limited by the Mandelstam–Tamm bound from those restricted by the Margolus–Levitin one. Our results offer a complete characterization of the physical quantities that become relevant in both the preparation and study of the dynamics of three-level states evolving towards orthogonality.

Characterization of Ion Energy Distribution in Inductively Coupled Argon Plasmas Sustained with Multiple Internal-Antenna Units

2008 ◽  
Vol 47 (8) ◽  
pp. 6900-6902 ◽  
Author(s):  
Kosuke Takenaka ◽  
Yuichi Setsuhara ◽  
Kazuaki Nishisaka ◽  
Akinori Ebe
Keyword(s):  
Energy Distribution ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
Inductively Coupled ◽  
Argon Plasmas ◽  
Internal Antenna

Proposal for dimensionality testing in QPQ

2018 ◽  
Vol 18 (13&14) ◽  
pp. 1125-1142
Author(s):  
Arpita Maitra ◽  
Bibhas Adhikari ◽  
Satyabrata Adhikari
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum System ◽  
Quantum State ◽  
Quantum Information Processing ◽  
Quantum States ◽  
Quantum Private Query ◽  
Unfair Advantage ◽  
Security Proofs

Recently, dimensionality testing of a quantum state has received extensive attention (Ac{\'i}n et al. Phys. Rev. Letts. 2006, Scarani et al. Phys. Rev. Letts. 2006). Security proofs of existing quantum information processing protocols rely on the assumption about the dimension of quantum states in which logical bits are encoded. However, removing such assumption may cause security loophole. In the present paper, we show that this is indeed the case. We choose two players' quantum private query protocol by Yang et al. (Quant. Inf. Process. 2014) as an example and show how one player can gain an unfair advantage by changing the dimension of subsystem of a shared quantum system. To resist such attack we propose dimensionality testing in a different way. Our proposal is based on CHSH like game. As we exploit CHSH like game, it can be used to test if the states are product states for which the protocol becomes completely vulnerable.

Sub- and super-fidelity as bounds for quantum fidelity

2009 ◽  
Vol 9 (1&2) ◽  
pp. 103-130
Author(s):  
J.A. Miszczak ◽  
Z. Puchala ◽  
P. Horodecki ◽  
A. Uhlmann ◽  
K. Zyczkowski
Keyword(s):  
Quantum System ◽  
Quantum States ◽  
Concave Functions ◽  
Two Dimensional ◽  
Quantum Fidelity

We derive several bounds on fidelity between quantum states. In particular we show that fidelity is bounded from above by a simple to compute quantity we call super--fidelity. It is analogous to another quantity called sub--fidelity. For any two states of a two--dimensional quantum system (N=2) all three quantities coincide. We demonstrate that sub-- and super--fidelity are concave functions. We also show that super--fidelity is super--multiplicative while sub--fidelity is sub--multiplicative and design feasible schemes to measure these quantities in an experiment.Super--fidelity can be used to define a distance between quantum states. With respect to this metric the set of quantum states forms a part of a N^2-1 dimensional hypersphere.

Radiation spectrum of hot excitons in Si nanocrystals

2016 ◽  
Vol 55 (4) ◽  
Author(s):  
Anton V. Gert ◽  
Irina N. Yassievich
Keyword(s):  
Energy Distribution ◽  
Silicon Nanocrystals ◽  
Energy Exchange ◽  
Relaxation Times ◽  
Exciton State ◽  
Time Interval ◽  
Pump Probe ◽  
Si Nanocrystals ◽  
Wide Energy ◽  
Probe Spectroscopy

The self-trapped exciton state (STE) is very important for the dynamics of hot excitons in photoexcited silicon nanocrystals embedded in a SiO2 matrix. This fact has been recently confirmed by the experimental data obtained by the femtosecond pump– probe spectroscopy technique in Amsterdam University. In this work we have studied the energy exchange between the exciton localized in the STE state and the hot exciton in the core of silicon nanocrystals and have shown that it determines the dynamics of the energy distribution of the hot excitons. Using the Monte-Carlo we have simulated the energy distribution of excitons in the time interval 10–100 ps after excitation. Thus the model of formation of the distribution of hot excitons in silicon nanocrystals is developed and the fast formation of the wide energy distribution is demonstrated. The form of the photoluminescence spectrum almost directly corresponds to the energy distribution of excitons in a silicon nanocrystal at a given moment. In the result we have found the relaxation times of hot excitons equal to 100 ps and the inner quantum efficiency of the ultrafast photoluminescence of about 0.1%. These values are close to the experimentally observed ones.

scholarly journals Concentration of Measure for Quantum States with a Fixed Expectation Value

2011 ◽  
Vol 303 (3) ◽  
pp. 785-824 ◽  
Author(s):  
Markus P. Müller ◽  
David Gross ◽  
Jens Eisert
Keyword(s):  
Quantum States ◽  
Concentration Of Measure ◽  
Expectation Value

Final characterization of InLambda delay standards for supplementary time interval comparison

2018 ◽  
Author(s):  
Albin Czubla ◽  
Piotr Szterk ◽  
Roman Osmyk ◽  
Borut Pinter ◽  
Rado Lapuh ◽  
...  
Keyword(s):  
Time Interval ◽  
Interval Comparison
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