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#### Quantum computers

, Article IEEE Potentials ; Volume 21, Issue 5 , 2002 , Pages 6-9 ; 02786648 (ISSN) ; Sharif University of Technology
2002

#### Zeilinger on information and reality

, Article Foundations of Science ; Volume 26, Issue 4 , 2021 , Pages 1007-1019 ; 12331821 (ISSN) ; Taqavi, M ; Shafiee, A ; Sharif University of Technology
Springer Science and Business Media B.V
2021

Abstract

According to Zeilinger’s information interpretation of quantum mechanics ‘the distinction between reality and our knowledge of reality, between reality and information, cannot be made. They are in a deep sense indistinguishable’. This is what we call Zeilinger’s thesis. This thesis has been criticized as a lapse into ‘informational immaterialism’ and amounting to nothing more than a tautology. However, we will argue that this criticism is based on a pre-Kantian view of reality, namely metaphysical realism which could be questioned on the basis of Putnam’s arguments. Furthermore, it will be argued that to understand Zeilinger’s thesis one should abandon the pre-Kantian perspective of...

#### Generalized noncommutative gauge theory

, Article Proceedings of the 13th Regional Conference on Mathematical Physics, Antalya ; 2013 , Pages 185-192 ; 9789814417525 (ISBN) ; Sharif University of Technology
2013

Abstract

The structure of the translationally invariant noncommutative field theory in determined and the corresponding gauge theory is presented

#### Logarithmic correction to the Cardy-Verlinde formula in topological Reissner-Nordström de Sitter space

, Article Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics ; Volume 573, Issue 1-4 , 2003 , Pages 173-180 ; 03702693 (ISSN) ; Sharif University of Technology
Elsevier
2003

Abstract

In this Letter we compute the leading order correction due to small statistical fluctuations around equilibrium, to the Cardy-Verlinde entropy formula (which is supposed to be an entropy formula of conformal field theory in any dimension) of a topological Reissner-Nordström black hole in de Sitter space. © 2003 Published by Elsevier B.V

#### Fundamental differences of substrate hydroxylation by high-valent Lron(IV)-Oxo models of cytochrome P450

, Article Inorganic Chemistry ; Volume 48, Issue 14 , 2009 , Pages 6661-6669 ; 00201669 (ISSN) ; Bagherzadeh, M ; Nam, W ; De Visser, S. P ; Sharif University of Technology
2009

Abstract

An Iron(lV)-oxo heme(+·) complex (Compound I, Cpd I) is the proposed active species of heme enzymes such as the cytochromes P450 and Is elusive; therefore, biomimetic studies on active site mimics give valuable Insight Into the fundamental properties of heme active species. In this work we present density functional theory (DFT) calculations on substrate hydroxylatlon by a Compound I mimic [FeIV=O(Por+̇)Cl] and its one-electron reduced form [FeIV=O(Por)Cl]-. Thus, recent experimental studies showed that [FeIV =O(Por)Cl]- is able to react with substrates via hydride transfer reactions [Jeong, Y. J.; Kang, Y.; Han, A.-R.; Lee, Y.-M.; Kotani, H.; Fukuzumi, S.; Nam, W. Angew. Chem., Int. Ed....

####
Studying of Chaotic Behavior in Some Classical and Quantum Systems

,
M.Sc. Thesis
Sharif University of Technology
;
Shafiee, Afshin
(Supervisor)
Abstract

Chaos is defined as an unpredictable and unrepeatable motion which has been observed in many classical systems such as unharmonic oscillators and turbulent currents in fluids. The common aspect of these types of motions is the deterministic nonlinear equation. On the other hand, quantum mechanics is a stochastic theory which is based on probabilistic description of quantum systems. These approaches lead to quantum chaos phenomenon which has been a controversial issue in the recent years. In the thesis, by studying the classical chaotic models such as kicked rotor, billiard model, excited hydrogen atom under microwave field and etc, we examine the existence of chaotic behavior in quantum...

#### The intramolecular cation-π interaction of some aryl amines and its drastic influence on the basicity of them: AIM and NBO analysis

, Article Computational and Theoretical Chemistry ; Vol. 1036 , May , 2014 , pp. 51-60 ; ISSN: 2210271X ; Fattahi, A ; Hashemi, M. M ; Sharif University of Technology
Abstract

In this study, drastic influence of the intramolecular cation-π interaction on the basicity of selected amines has been considered. The optimized minimum energy geometries of different studied amines and their protonated structures were determined by using DFT calculations at the B3LYP/6-311++G(d,p) level of theory. Geometry optimizations indicate that the most stable structures of protonated amines are stabilized by intramolecular cation-π interaction. The proton affinity (PA) of selected amines is controlled by the strength of intramolecular cation-π interaction of ammonium with aromatic ring. These cation-π interactions strongly influence the basicity of amines. Natural bond orbital (NBO)...

#### Can anion interaction accelerate transformation of cytosine tautomers? Detailed view form QTAIM analysis

, Article Structural Chemistry ; Volume 23, Issue 6 , 2012 , Pages 1843-1855 ; 10400400 (ISSN) ; Tehrani, Z. A ; Fattahi, A ; Jamshidi, Z ; Sharif University of Technology
Abstract

The relative stabilities and noncovalent interactions of the six low-lying energy tautomers of cytosine nucleobase with some biological anions (such as F-, Cl-, and CN-) have been investigated in gas phase by density functional theory (DFT) method in conjunction with 6-311++G (d,p) atomic basis set. Furthermore, to systematically investigate all possible tautomerisms from cytosine induced by proton transfer, we describe a study of structural tautomer interconversion in the gas phase and in a continuum solvent using DFT calculation. We carried out geometrical optimizations with the integral equation formalism of polarizable continuum (IEF-PCM) model to account for the solvent effect, and the...

#### Macroscopic superpositions via nested interferometry: Finite temperature and decoherence considerations

, Article New Journal of Physics ; Volume 14 , November , 2012 ; 13672630 (ISSN) ; Jeffrey, E ; Ghobadi, R ; Simon, C ; Bouwmeester, D ; Sharif University of Technology
2012

Abstract

Recently, there has been much interest in optomechanical devices for the production of macroscopic quantum states. Here we focus on a proposed scheme for achieving macroscopic superpositions via nested interferometry. We consider the effects of finite temperature on the superposition produced. We also investigate in detail the scheme's feasibility for probing various novel decoherence mechanisms

#### Variation of the lateral Casimir force between corrugated conductors due to the presence of a dielectric slab

, Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 86, Issue 2 , 2012 ; 10502947 (ISSN) ; Soltani, M ; Zakeri, P ; Jafari, S. A ; Sharif University of Technology
APS
2012

Abstract

We investigate the lateral Casimir interaction between two corrugated conductors when they enclose a dielectric slab. The magnitude of the lateral Casimir force can be changed due to the presence of a dielectric slab between them, and it strongly depends on the thickness (d) and dielectric function of the slab and also on the position of the slab with respect to the conductors. In addition, the distance between the conductors (H) and their corrugation wavelengths play important roles in tuning the lateral Casimir interaction. For fixed d and H, quite interestingly, the magnitude of the lateral Casimir force varies when the position of the slab with respect to conductors changes, and it has a...

#### Modeling of Pull-In Instability of Nano/Micromirrors Under the Combined Effect of Capillary and Casimir Forces

, Article International Journal of Optomechatronics ; Volume 5, Issue 4 , Dec , 2011 , Pages 378-392 ; 15599612 (ISSN) ; Darvishian, A ; Ahmaidan, M. T ; Sharif University of Technology
2011

Abstract

In the current article the effect of the Casimir force on the static behavior and pull-in characteristics of nano/micromirrors under capillary force is investigated. At the first, the dimensionless equation governing the static behavior of nano/micromirrors is obtained. The dependency of the critical tilting angle on the physical and geometrical parameters of the nano/micromirror and its supporting torsional beams is investigated. It is found that the Casimir effect can considerably reduce the pull-in instability limits of the nano/micromirror. It is also found that rotation angle of the mirror under capillary force highly depends on the Casimir force applied to the mirror. Finally the...

#### Critical assessment on the minimal work approach in quantum thermodynamics

, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 42, Issue 3 , 2010 , Pages 488-490 ; 13869477 (ISSN) ; Shafiee, A ; Sharif University of Technology
Abstract

According to a well-known approach in quantum thermodynamics, the characteristics of a system in a process can be estimated by calculating work in the process. Here, we are going to show that this approach cannot provide with us a clear depiction of the second law of thermodynamics in some specific (but simple) processes

#### Universal superposition of orthogonal states

, Article Physical Review A ; Volume 96, Issue 5 , 2017 ; 24699926 (ISSN) ; Kianvash, F ; Karimipour, V
Abstract

It is known that no quantum process can produce a predetermined superposition of unknown arbitrary states. It has already been shown that with some partial information about the states, one can produce with some probability such superpositions. In general the success probability of these machines, even for orthogonal states, are less than unity. Here we show that there are specific machines that can produce superpositions of orthogonal qubit states with unit probability. © 2017 American Physical Society

#### Quantum states with equal unlockable correlations and quantum discord

, Article Physical Review A ; Volume 98, Issue 3 , 2018 ; 24699926 (ISSN) ; Mani, A ; Bahrampour, A ; Sharif University of Technology
American Physical Society
2018

Abstract

In the context of quantum locking of classical correlations protocols, the condition for equality of the amount of unlockable correlations and quantum discord of general classical-quantum states is investigated. Based on this condition, the structure of such general states is obtained. This condition imposes two constraints on the structure of general classical-quantum states. After presenting the interpretation of these constraints, their role in quantum locking protocols is discussed. Finally, the derived structure is generalized to quantum-quantum states and the amount of their unlockable correlations is interpreted in terms of their symmetric discord. © 2018 American Physical Society

#### Feedforward-assisted coherent-state comparison amplifier

, Article Physical Review A ; Volume 100, Issue 4 , 2019 ; 24699926 (ISSN) ; Marjan, N ; Bahrampour, A. R ; Sharif University of Technology
American Physical Society
2019

Abstract

Quantum optical coherent-state comparison amplifiers are nondeterministic devices which can amplify rather noiselessly a weak coherent state with an unknown phase from a finite discrete set. The high fidelity and high success probability of this amplifier are accomplished by a comparison stage and some photon subtraction stages. Due to the heralding nature of these amplifiers, they work part of the time. Here, we propose a feedforward protocol to increase the heralded times by correcting the incorrect guess. Hence, we enhance the fidelity and success probability more. Finally, the schematic experimental configuration of the feedforward-assisted coherent-state comparison amplifier is...

#### Power of a shared singlet state in comparison to a shared reference frame

, Article Physical Review A ; Volume 100, Issue 2 , 2019 ; 24699926 (ISSN) ; Mani, A ; Karimipour, V ; Sharif University of Technology
American Physical Society
2019

Abstract

We show that a shared singlet state (SSS) can supersede a shared reference frame (SRF) in certain quantum communication tasks, i.e., tasks in which two remote players are required to estimate certain parameters of a two-particle state sent to them. This shows that task-specific values of resources may be somewhat different from their common values based on their exchange possibilities. © 2019 American Physical Society. ©2019 American Physical Society

#### “It from Bit” and Quantum Mechanics

, Article Foundations of Science ; 2019 ; 12331821 (ISSN) ; Shafiee, A ; Taqavi, M ; Sharif University of Technology
Springer
2019

Abstract

John Archibald Wheeler is one of the staunchest advocates of the idea that information is more fundamental than anything else in physics. In this paper, we examine the status of this idea summarized in Wheeler’s slogan ‘it from bit’ in the context of Bohmian Mechanics and spontaneous collapse models. We will argue that any question about the status of ‘it from bit’ crucially depends on the particular interpretation of these theories one favors. © 2019, Springer Nature B.V

#### “It from Bit” and Quantum Mechanics

, Article Foundations of Science ; 2019 ; 12331821 (ISSN) ; Shafiee, A ; Taqavi, M ; Sharif University of Technology
Springer
2019

Abstract

John Archibald Wheeler is one of the staunchest advocates of the idea that information is more fundamental than anything else in physics. In this paper, we examine the status of this idea summarized in Wheeler’s slogan ‘it from bit’ in the context of Bohmian Mechanics and spontaneous collapse models. We will argue that any question about the status of ‘it from bit’ crucially depends on the particular interpretation of these theories one favors. © 2019, Springer Nature B.V

#### “It from Bit” and quantum mechanics

, Article Foundations of Science ; Volume 25, Issue 2 , 2020 , Pages 375-384 ; Shafiee, A ; Taqavi, M ; Sharif University of Technology
Springer
2020

Abstract

John Archibald Wheeler is one of the staunchest advocates of the idea that information is more fundamental than anything else in physics. In this paper, we examine the status of this idea summarized in Wheeler’s slogan ‘it from bit’ in the context of Bohmian Mechanics and spontaneous collapse models. We will argue that any question about the status of ‘it from bit’ crucially depends on the particular interpretation of these theories one favors. © 2019, Springer Nature B.V

#### Memory effects in spin-chain channels for information transmission

, Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 77, Issue 5 , 2008 ; 10502947 (ISSN) ; Burgarth, D ; Mancini, S ; Bose, S ; Sharif University of Technology
2008

Abstract

We investigate the multiple use of a ferromagnetic spin chain for quantum and classical communications without resetting. We find that the memory of the state transmitted during the first use makes the spin chain a qualitatively different quantum channel during the second transmission, for which we find the relevant Kraus operators. We propose a parameter to quantify the amount of memory in the channel and find that it influences the quality of the channel, as reflected through fidelity and entanglement transmissible during the second use. For certain evolution times, the memory allows the channel to exceed the memoryless classical capacity (achieved by separable inputs) and in some cases it...