New Insights Into the Physical Processes That Underpin Cell Division and the Emergence of Different Cellular and Multicellular Structures
Total Page:16
File Type:pdf, Size:1020Kb

Load more
Recommended publications
-
The Theory of Quantum Coherence María García Díaz
ADVERTIMENT. Lʼaccés als continguts dʼaquesta tesi queda condicionat a lʼacceptació de les condicions dʼús establertes per la següent llicència Creative Commons: http://cat.creativecommons.org/?page_id=184 ADVERTENCIA. El acceso a los contenidos de esta tesis queda condicionado a la aceptación de las condiciones de uso establecidas por la siguiente licencia Creative Commons: http://es.creativecommons.org/blog/licencias/ WARNING. The access to the contents of this doctoral thesis it is limited to the acceptance of the use conditions set by the following Creative Commons license: https://creativecommons.org/licenses/?lang=en Universitat Aut`onomade Barcelona The theory of quantum coherence by Mar´ıaGarc´ıaD´ıaz under supervision of Prof. Andreas Winter A thesis submitted in partial fulfillment for the degree of Doctor of Philosophy in Unitat de F´ısicaTe`orica:Informaci´oi Fen`omensQu`antics Departament de F´ısica Facultat de Ci`encies Bellaterra, December, 2019 “The arts and the sciences all draw together as the analyst breaks them down into their smallest pieces: at the hypothetical limit, at the very quick of epistemology, there is convergence of speech, picture, song, and instigating force.” Daniel Albright, Quantum poetics: Yeats, Pound, Eliot, and the science of modernism Abstract Quantum coherence, or the property of systems which are in a superpo- sition of states yielding interference patterns in suitable experiments, is the main hallmark of departure of quantum mechanics from classical physics. Besides its fascinating epistemological implications, quantum coherence also turns out to be a valuable resource for quantum information tasks, and has even been used in the description of fundamental biological processes. -
Path Integrals in Quantum Mechanics
Path Integrals in Quantum Mechanics Dennis V. Perepelitsa MIT Department of Physics 70 Amherst Ave. Cambridge, MA 02142 Abstract We present the path integral formulation of quantum mechanics and demon- strate its equivalence to the Schr¨odinger picture. We apply the method to the free particle and quantum harmonic oscillator, investigate the Euclidean path integral, and discuss other applications. 1 Introduction A fundamental question in quantum mechanics is how does the state of a particle evolve with time? That is, the determination the time-evolution ψ(t) of some initial | i state ψ(t ) . Quantum mechanics is fully predictive [3] in the sense that initial | 0 i conditions and knowledge of the potential occupied by the particle is enough to fully specify the state of the particle for all future times.1 In the early twentieth century, Erwin Schr¨odinger derived an equation specifies how the instantaneous change in the wavefunction d ψ(t) depends on the system dt | i inhabited by the state in the form of the Hamiltonian. In this formulation, the eigenstates of the Hamiltonian play an important role, since their time-evolution is easy to calculate (i.e. they are stationary). A well-established method of solution, after the entire eigenspectrum of Hˆ is known, is to decompose the initial state into this eigenbasis, apply time evolution to each and then reassemble the eigenstates. That is, 1In the analysis below, we consider only the position of a particle, and not any other quantum property such as spin. 2 D.V. Perepelitsa n=∞ ψ(t) = exp [ iE t/~] n ψ(t ) n (1) | i − n h | 0 i| i n=0 X This (Hamiltonian) formulation works in many cases. -
Quantum Biology: an Update and Perspective
quantum reports Review Quantum Biology: An Update and Perspective Youngchan Kim 1,2,3 , Federico Bertagna 1,4, Edeline M. D’Souza 1,2, Derren J. Heyes 5 , Linus O. Johannissen 5 , Eveliny T. Nery 1,2 , Antonio Pantelias 1,2 , Alejandro Sanchez-Pedreño Jimenez 1,2 , Louie Slocombe 1,6 , Michael G. Spencer 1,3 , Jim Al-Khalili 1,6 , Gregory S. Engel 7 , Sam Hay 5 , Suzanne M. Hingley-Wilson 2, Kamalan Jeevaratnam 4, Alex R. Jones 8 , Daniel R. Kattnig 9 , Rebecca Lewis 4 , Marco Sacchi 10 , Nigel S. Scrutton 5 , S. Ravi P. Silva 3 and Johnjoe McFadden 1,2,* 1 Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford GU2 7XH, UK; [email protected] (Y.K.); [email protected] (F.B.); e.d’[email protected] (E.M.D.); [email protected] (E.T.N.); [email protected] (A.P.); [email protected] (A.S.-P.J.); [email protected] (L.S.); [email protected] (M.G.S.); [email protected] (J.A.-K.) 2 Department of Microbial and Cellular Sciences, School of Bioscience and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK; [email protected] 3 Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, UK; [email protected] 4 School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK; [email protected] (K.J.); [email protected] (R.L.) 5 Manchester Institute of Biotechnology, Department of Chemistry, The University of Manchester, -
Optimization of Transmon Design for Longer Coherence Time
Optimization of transmon design for longer coherence time Simon Burkhard Semester thesis Spring semester 2012 Supervisor: Dr. Arkady Fedorov ETH Zurich Quantum Device Lab Prof. Dr. A. Wallraff Abstract Using electrostatic simulations, a transmon qubit with new shape and a large geometrical size was designed. The coherence time of the qubits was increased by a factor of 3-4 to about 4 µs. Additionally, a new formula for calculating the coupling strength of the qubit to a transmission line resonator was obtained, allowing reasonably accurate tuning of qubit parameters prior to production using electrostatic simulations. 2 Contents 1 Introduction 4 2 Theory 5 2.1 Coplanar waveguide resonator . 5 2.1.1 Quantum mechanical treatment . 5 2.2 Superconducting qubits . 5 2.2.1 Cooper pair box . 6 2.2.2 Transmon . 7 2.3 Resonator-qubit coupling (Jaynes-Cummings model) . 9 2.4 Effective transmon network . 9 2.4.1 Calculation of CΣ ............................... 10 2.4.2 Calculation of β ............................... 10 2.4.3 Qubits coupled to 2 resonators . 11 2.4.4 Charge line and flux line couplings . 11 2.5 Transmon relaxation time (T1) ........................... 11 3 Transmon simulation 12 3.1 Ansoft Maxwell . 12 3.1.1 Convergence of simulations . 13 3.1.2 Field integral . 13 3.2 Optimization of transmon parameters . 14 3.3 Intermediate transmon design . 15 3.4 Final transmon design . 15 3.5 Comparison of the surface electric field . 17 3.6 Simple estimate of T1 due to coupling to the charge line . 17 3.7 Simulation of the magnetic flux through the split junction . -
Physics, Biology and the Origin of Life: the Physicians' View Geoffrey Goodman Phd1 and M
IMAJ • VOL 13 • DeceMber 2011 PERSPECTIVE Physics, Biology and the Origin of Life: The Physicians' View Geoffrey Goodman PhD1 and M. Eric Gershwin MD2 1Kfar Vradim, Israel 2Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis School of Medicine, Davis, CA, USA environment and were very much concerned with the insepa- ABSTRACT: Physicians have a great interest in discussions of life and its rable issue of 'what' is life and 'how' it relates to inanimate origin, including life's persistence through successive cycles matter. Physicians of those eras were more concerned about of self-replication under extreme climatic and man-made religion and the role of man and God than about physical sci- trials and tribulations. We review here the fundamental ence. One wonders what they would think today, with physical processes that, contrary to human intuition, life may be science dominated and puzzled by the apparent incompatibility seen heuristically as an ab initio, fundamental process between two fundamental concepts: general relativity (gravi- at the interface between the complementary forces of tational) theory that views matter-energy as an expression of gravitation and quantum mechanics. Analogies can predict a time-space continuum and quantum theory that considers applications of quantum mechanics to human physiology matter-energy in terms of discrete quantities (quanta) and in addition to that already being applied, in particular to waves and their counterintuitively weird behavior. The long- aspects of brain activity and pathology. This potential will also extend eventually to, for example, autoimmunity, held desire to unify these two fundamental laws of physics in genetic selection and aging. -
Quantum Trajectories: Real Or Surreal?
entropy Article Quantum Trajectories: Real or Surreal? Basil J. Hiley * and Peter Van Reeth * Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK * Correspondence: [email protected] (B.J.H.); [email protected] (P.V.R.) Received: 8 April 2018; Accepted: 2 May 2018; Published: 8 May 2018 Abstract: The claim of Kocsis et al. to have experimentally determined “photon trajectories” calls for a re-examination of the meaning of “quantum trajectories”. We will review the arguments that have been assumed to have established that a trajectory has no meaning in the context of quantum mechanics. We show that the conclusion that the Bohm trajectories should be called “surreal” because they are at “variance with the actual observed track” of a particle is wrong as it is based on a false argument. We also present the results of a numerical investigation of a double Stern-Gerlach experiment which shows clearly the role of the spin within the Bohm formalism and discuss situations where the appearance of the quantum potential is open to direct experimental exploration. Keywords: Stern-Gerlach; trajectories; spin 1. Introduction The recent claims to have observed “photon trajectories” [1–3] calls for a re-examination of what we precisely mean by a “particle trajectory” in the quantum domain. Mahler et al. [2] applied the Bohm approach [4] based on the non-relativistic Schrödinger equation to interpret their results, claiming their empirical evidence supported this approach producing “trajectories” remarkably similar to those presented in Philippidis, Dewdney and Hiley [5]. However, the Schrödinger equation cannot be applied to photons because photons have zero rest mass and are relativistic “particles” which must be treated differently. -
Perturbation Theory and Exact Solutions
PERTURBATION THEORY AND EXACT SOLUTIONS by J J. LODDER R|nhtdnn Report 76~96 DISSIPATIVE MOTION PERTURBATION THEORY AND EXACT SOLUTIONS J J. LODOER ASSOCIATIE EURATOM-FOM Jun»»76 FOM-INST1TUUT VOOR PLASMAFYSICA RUNHUIZEN - JUTPHAAS - NEDERLAND DISSIPATIVE MOTION PERTURBATION THEORY AND EXACT SOLUTIONS by JJ LODDER R^nhuizen Report 76-95 Thisworkwat performed at part of th«r«Mvchprogmmncof thcHMCiattofiafrccmentof EnratoniOTd th« Stichting voor FundtmenteelOiutereoek der Matctk" (FOM) wtihnnmcWMppoft from the Nederhmdie Organiutic voor Zuiver Wetemchap- pcigk Onderzoek (ZWO) and Evntom It it abo pabHtfMd w a the* of Ac Univenrty of Utrecht CONTENTS page SUMMARY iii I. INTRODUCTION 1 II. GENERALIZED FUNCTIONS DEFINED ON DISCONTINUOUS TEST FUNC TIONS AND THEIR FOURIER, LAPLACE, AND HILBERT TRANSFORMS 1. Introduction 4 2. Discontinuous test functions 5 3. Differentiation 7 4. Powers of x. The partie finie 10 5. Fourier transforms 16 6. Laplace transforms 20 7. Hubert transforms 20 8. Dispersion relations 21 III. PERTURBATION THEORY 1. Introduction 24 2. Arbitrary potential, momentum coupling 24 3. Dissipative equation of motion 31 4. Expectation values 32 5. Matrix elements, transition probabilities 33 6. Harmonic oscillator 36 7. Classical mechanics and quantum corrections 36 8. Discussion of the Pu strength function 38 IV. EXACTLY SOLVABLE MODELS FOR DISSIPATIVE MOTION 1. Introduction 40 2. General quadratic Kami1tonians 41 3. Differential equations 46 4. Classical mechanics and quantum corrections 49 5. Equation of motion for observables 51 V. SPECIAL QUADRATIC HAMILTONIANS 1. Introduction 53 2. Hamiltcnians with coordinate coupling 53 3. Double coordinate coupled Hamiltonians 62 4. Symmetric Hamiltonians 63 i page VI. DISCUSSION 1. Introduction 66 ?. -
Neuroreceptor Activation by Vibration-Assisted Tunneling
OPEN Neuroreceptor Activation by SUBJECT AREAS: Vibration-Assisted Tunneling BIOPHYSICAL CHEMISTRY Ross D. Hoehn1, David Nichols2, Hartmut Neven3 & Sabre Kais4,5,6 MECHANISM OF ACTION 1Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA, 2Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA,3 Google, Venice, CA 90291, USA,4 Department of Received 5 20 October 2014 Chemistry, Purdue University, West Lafayette, IN 47907, USA, Departments of Physics, Purdue University, West Lafayette, IN 47907, USA,6 Qatar Environment and Energy Research Institute, Qatar Foundation, Doha, Qatar. Accepted 20 March 2015 G protein-coupled receptors (GPCRs) constitute a large family of receptor proteins that sense molecular Published signals on the exterior of a cell and activate signal transduction pathways within the cell. Modeling how an 24 April 2015 agonist activates such a receptor is fundamental for an understanding of a wide variety of physiological processes and it is of tremendous value for pharmacology and drug design. Inelastic electron tunneling spectroscopy (IETS) has been proposed as a model for the mechanism by which olfactory GPCRs are activated by a bound agonist. We apply this hyothesis to GPCRs within the mammalian nervous system Correspondence and using quantum chemical modeling. We found that non-endogenous agonists of the serotonin receptor share requests for materials a particular IET spectral aspect both amongst each other and with the serotonin molecule: a peak whose should be addressed to intensity scales with the known agonist potencies. We propose an experiential validation of this model by S.K. (kais@purdue. utilizing lysergic acid dimethylamide (DAM-57), an ergot derivative, and its deuterated isotopologues; we also provide theoretical predictions for comparison to experiment. -
On Coherence and the Transverse Spatial Extent of a Neutron Wave Packet
On coherence and the transverse spatial extent of a neutron wave packet C.F. Majkrzak, N.F. Berk, B.B. Maranville, J.A. Dura, Center for Neutron Research, and T. Jach Materials Measurement Laboratory, National Institute of Standards and Technology Gaithersburg, MD 20899 (18 November 2019) Abstract In the analysis of neutron scattering measurements of condensed matter structure, it normally suffices to treat the incident and scattered neutron beams as if composed of incoherent distributions of plane waves with wavevectors of different magnitudes and directions which are taken to define an instrumental resolution. However, despite the wide-ranging applicability of this conventional treatment, there are cases in which the wave function of an individual neutron in the beam must be described more accurately by a spatially localized packet, in particular with respect to its transverse extent normal to its mean direction of propagation. One such case involves the creation of orbital angular momentum (OAM) states in a neutron via interaction with a material device of a given size. It is shown in the work reported here that there exist two distinct measures of coherence of special significance and utility for describing neutron beams in scattering studies of materials in general. One measure corresponds to the coherent superposition of basis functions and their wavevectors which constitute each individual neutron packet state function whereas the other measure can be associated with an incoherent distribution of mean wavevectors of the individual neutron packets in a beam. Both the distribution of the mean wavevectors of individual packets in the beam as well as the wavevector components of the superposition of basis functions within an individual packet can contribute to the conventional notion of instrumental resolution. -
Chapter 5 Angular Momentum and Spin
Chapter 5 Angular Momentum and Spin I think you and Uhlenbeck have been very lucky to get your spinning electron published and talked about before Pauli heard of it. It appears that more than a year ago Kronig believed in the spinning electron and worked out something; the first person he showed it to was Pauli. Pauli rediculed the whole thing so much that the first person became also the last ... – Thompson (in a letter to Goudsmit) The first experiment that is often mentioned in the context of the electron’s spin and magnetic moment is the Einstein–de Haas experiment. It was designed to test Amp`ere’s idea that magnetism is caused by “molecular currents”. Such circular currents, while generating a magnetic field, would also contribute to the angular momentum of a ferromagnet. Therefore a change in the direction of the magnetization induced by an external field has to lead to a small rotation of the material in order to preserve the total angular momentum. For a quantitative understanding of the effect we consider a charged particle of mass m and charge q rotating with velocity v on a circle of radius r. Since the particle passes through its orbit v/(2πr) times per second the resulting current I = qv/(2πr), which encircles an area A = r2π, generates a magnetic dipole moment µ = IA/c, qv IA qv r2π qvr q q I = µ = = = = L = γL, γ = , (5.1) 2πr ⇒ c 2πr c 2c 2mc 2mc where L~ = m~r ~v is the angular momentum. Now the essential observation is that the × gyromagnetic ratio γ = µ/L is independent of the radius of the motion. -
Partial Coherence Effects on the Imaging of Small Crystals Using Coherent X-Ray Diffraction
INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS: CONDENSED MATTER J. Phys.: Condens. Matter 13 (2001) 10593–10611 PII: S0953-8984(01)25635-5 Partial coherence effects on the imaging of small crystals using coherent x-ray diffraction I A Vartanyants1 and I K Robinson Department of Physics, University of Illinois, 1110 West Green Street, Urbana, IL 61801, USA Received 8 June 2001 Published 9 November 2001 Online at stacks.iop.org/JPhysCM/13/10593 Abstract Recent achievements in experimental and computational methods have opened up the possibility of measuring and inverting the diffraction pattern from a single-crystalline particle on the nanometre scale. In this paper, a theoretical approach to the scattering of purely coherent and partially coherent x-ray radiation by such particles is discussed in detail. Test calculations based on the iterative algorithms proposed initially by Gerchberg and Saxton and generalized by Fienup are applied to reconstruct the shape of the scattering crystals. It is demonstrated that partially coherent radiation produces a small area of high intensity in the reconstructed image of the particle. (Some figures in this article are in colour only in the electronic version) 1. Introduction Even in the early years of x-ray studies [1–4] it was already understood that the diffraction pattern from small perfect crystals is directly connected with the shape of these crystals through Fourier transformation. Of course, in a real diffraction experiment on a ‘powder’ sample, where many particles with different shapes and orientations are illuminated by an incoherent beam, only an averaged shape of these particles can be obtained. -
Laurent Nottale CNRS LUTH, Paris-Meudon Observatory Scales in Nature
Laurent Nottale CNRS LUTH, Paris-Meudon Observatory http://www.luth.obspm.fr/~luthier/nottale/ Scales in nature 1 10 -33 cm Planck scale 10 -28 cm Grand Unification 10 10 accelerators: today's limit 10 -16 cm electroweak unification 20 10 3 10 -13 cm quarks 4 10 -11 cm electron Compton length 1 Angstrom Bohr radius atoms 30 virus 10 40 microns bacteries 1 m human scale 40 10 6000 km Earth radius 700000 km Sun radius 1 millard km Solar System 50 10 1 parsec distances to Stars 10 kpc Milky Way radius 1 Mpc Clusters of galaxies 60 100 Mpc very large structures 10 28 10 cm Cosmological scale Scales of living systems Relations between length-scales and mass- scales l/lP = m/mP (GR) l/lP = mP / m (QM) FIRST PRINCIPLES RELATIVITY COVARIANCE EQUIVALENCE weak / strong Action Geodesical CONSERVATION Noether SCALE RELATIVITY Continuity + Giving up the hypothesis Generalize relativity of differentiability of of motion ? space-time Transformations of non- differentiable coordinates ? …. Theorem Explicit dependence of coordinates in terms of scale variables + divergence FRACTAL SPACE-TIME Complete laws of physics by fundamental scale laws Constrain the new scale laws… Principle of scale relativity Generalized principle Scale covariance of equivalence Linear scale-laws: “Galilean” Linear scale-laws : “Lorentzian” Non-linear scale-laws: self-similarity, varying fractal dimension, general scale-relativity, constant fractal dimension, scale covariance, scale dynamics, scale invariance invariant limiting scales gauge fields Continuity + Non-differentiability