Efficient Quantum Algorithms for Simulating Lindblad Evolution
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A View on Stochastic Differential Equations Derived from Quantum Optics
A VIEW ON STOCHASTIC DIFFERENTIAL EQUATIONS DERIVED FROM QUANTUM OPTICS FRANCO FAGNOLA AND ROLANDO REBOLLEDO Quantum Optics has had an impressive development during the last two decades. Laser–based devices are invading our every–day life: printers, pointers, a new surgical technology replacing the old scalpel, transport of information, among many other applications which give the idea of a well established theory. Even though, various theoretical problems remain open. In particular Quantum Optics continues to inspire mathematicians in their own research. This survey is aimed at giving a taste of some mathematical problems raised by Quantum Optics within the field of Stochastic Analysis. Espe- cially, we want to show the interplay between classical and non commutative stochastic differential equations associated to the so called master equations of Quantum Optics. Contents 1. Introduction 2 1.1. Notations 3 1.2. Deriving the master equation 4 2. The associated Quantum Stochastic Differential Equation 7 2.1. Quantum noises in continuous time 8 2.2. The master equation for the quantum cocycle 9 2.3. The Quantum Markov Flow 10 3. Unravelling: classical stochastic processes related to quantum flows 12 3.1. The algebra generated by the number operator 12 3.2. Position, momentum and their algebras 13 3.3. The evolution on AN , Aq, Ap. 15 4. Stationary state and the convergence towards the equilibrium 16 References 18 Research partially supported by FONDECYT grant 1960917 and the “C´atedraPresi- dencial en An´alisis Estoc´astico y F´ısica Matem´atica”. 1 2 FRANCO FAGNOLA AND ROLANDO REBOLLEDO 1. Introduction A major breakthrough of Probability Theory during the twentieth cen- tury is the advent of Stochastic Analysis with all its branches, which is being currently used in modelling phenomena in different sciences. -
On the Tightness of the Buhrman-Cleve-Wigderson Simulation
On the tightness of the Buhrman-Cleve-Wigderson simulation Shengyu Zhang Department of Computer Science and Engineering, The Chinese University of Hong Kong. [email protected] Abstract. Buhrman, Cleve and Wigderson gave a general communica- 1 1 n n tion protocol for block-composed functions f(g1(x ; y ); ··· ; gn(x ; y )) by simulating a decision tree computation for f [3]. It is also well-known that this simulation can be very inefficient for some functions f and (g1; ··· ; gn). In this paper we show that the simulation is actually poly- nomially tight up to the choice of (g1; ··· ; gn). This also implies that the classical and quantum communication complexities of certain block- composed functions are polynomially related. 1 Introduction Decision tree complexity [4] and communication complexity [7] are two concrete models for studying computational complexity. In [3], Buhrman, Cleve and Wigderson gave a general method to design communication 1 1 n n protocol for block-composed functions f(g1(x ; y ); ··· ; gn(x ; y )). The basic idea is to simulate the decision tree computation for f, with queries i i of the i-th variable answered by a communication protocol for gi(x ; y ). In the language of complexity measures, this result gives CC(f(g1; ··· ; gn)) = O~(DT(f) · max CC(gi)) (1) i where CC and DT are the communication complexity and the decision tree complexity, respectively. This simulation holds for all the models: deterministic, randomized and quantum1. It is also well known that the communication protocol by the above simulation can be very inefficient. -
Thesis Is Owed to Him, Either Directly Or Indirectly
UvA-DARE (Digital Academic Repository) Quantum Computing and Communication Complexity de Wolf, R.M. Publication date 2001 Document Version Final published version Link to publication Citation for published version (APA): de Wolf, R. M. (2001). Quantum Computing and Communication Complexity. Institute for Logic, Language and Computation. General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl) Download date:30 Sep 2021 Quantum Computing and Communication Complexity Ronald de Wolf Quantum Computing and Communication Complexity ILLC Dissertation Series 2001-06 For further information about ILLC-publications, please contact Institute for Logic, Language and Computation Universiteit van Amsterdam Plantage Muidergracht 24 1018 TV Amsterdam phone: +31-20-525 6051 fax: +31-20-525 5206 e-mail: [email protected] homepage: http://www.illc.uva.nl/ Quantum Computing and Communication Complexity Academisch Proefschrift ter verkrijging van de graad van doctor aan de Universiteit van Amsterdam op gezag van de Rector Magni¯cus prof.dr. -
2020 Volume 16 Issues
Issues 1-2 2020 Volume 16 The Journal on Advanced Studies in Theoretical and Experimental Physics, including Related Themes from Mathematics PROGRESS IN PHYSICS “All scientists shall have the right to present their scientific research results, in whole or in part, at relevant scientific conferences, and to publish the same in printed scientific journals, electronic archives, and any other media.” — Declaration of Academic Freedom, Article 8 ISSN 1555-5534 The Journal on Advanced Studies in Theoretical and Experimental Physics, including Related Themes from Mathematics PROGRESS IN PHYSICS A quarterly issue scientific journal, registered with the Library of Congress (DC, USA). This journal is peer reviewed and included in the abstracting and indexing coverage of: Mathematical Reviews and MathSciNet (AMS, USA), DOAJ of Lund University (Sweden), Scientific Commons of the University of St. Gallen (Switzerland), Open-J-Gate (India), Referativnyi Zhurnal VINITI (Russia), etc. Electronic version of this journal: http://www.ptep-online.com Advisory Board Dmitri Rabounski, Editor-in-Chief, Founder Florentin Smarandache, Associate Editor, Founder April 2020 Vol. 16, Issue 1 Larissa Borissova, Associate Editor, Founder Editorial Board CONTENTS Pierre Millette [email protected] Dorda G. The Interpretation of the Hubble-Effect and of Human Vision Based on the Andreas Ries Differentiated Structure of Space . .3 [email protected] Tselnik F. Predictability Is Fundamental . .10 Gunn Quznetsov [email protected] Dorda G. The Interpretation of Sound on the Basis of the Differentiated Structure of Ebenezer Chifu Three-Dimensional Space . 15 [email protected] Nyambuya G. G. A Pedestrian Derivation of Heisenberg’s Uncertainty Principle on Stochastic Phase-Space . -
Pip-2020-01.Pdf
Issue 1 2020 Volume 16 The Journal on Advanced Studies in Theoretical and Experimental Physics, including Related Themes from Mathematics PROGRESS IN PHYSICS “All scientists shall have the right to present their scientific research results, in whole or in part, at relevant scientific conferences, and to publish the same in printed scientific journals, electronic archives, and any other media.” — Declaration of Academic Freedom, Article 8 ISSN 1555-5534 The Journal on Advanced Studies in Theoretical and Experimental Physics, including Related Themes from Mathematics PROGRESS IN PHYSICS A quarterly issue scientific journal, registered with the Library of Congress (DC, USA). This journal is peer reviewed and included in the abstracting and indexing coverage of: Mathematical Reviews and MathSciNet (AMS, USA), DOAJ of Lund University (Sweden), Scientific Commons of the University of St. Gallen (Switzerland), Open-J-Gate (India), Referativnyi Zhurnal VINITI (Russia), etc. Electronic version of this journal: http://www.ptep-online.com Advisory Board Dmitri Rabounski, Editor-in-Chief, Founder Florentin Smarandache, Associate Editor, Founder April 2020 Vol. 16, Issue 1 Larissa Borissova, Associate Editor, Founder Editorial Board CONTENTS Pierre Millette [email protected] Dorda G. The Interpretation of the Hubble-Effect and of Human Vision Based on the Andreas Ries Differentiated Structure of Space . .3 [email protected] Tselnik F. Predictability Is Fundamental . .10 Gunn Quznetsov [email protected] Dorda G. The Interpretation of Sound on the Basis of the Differentiated Structure of Ebenezer Chifu Three-Dimensional Space . 15 [email protected] Nyambuya G. G. A Pedestrian Derivation of Heisenberg’s Uncertainty Principle on Stochastic Phase-Space . -
Using a Lindbladian Approach to Model Decoherence in Two Coupled Nuclear Spins Via Correlated Phase Damping and Amplitude Damping Noise Channels
Pramana – J. Phys. (2020) 94:160 © Indian Academy of Sciences https://doi.org/10.1007/s12043-020-02027-3 Using a Lindbladian approach to model decoherence in two coupled nuclear spins via correlated phase damping and amplitude damping noise channels HARPREET SINGH1,2,ARVIND1 and KAVITA DORAI1 ,∗ 1Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81 Knowledge City, P.O. Manauli, Mohali 140 306, India 2Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany ∗Corresponding author. E-mail: [email protected] MS received 18 April 2020; revised 25 July 2020; accepted 18 August 2020 Abstract. In this work, we studied the relaxation dynamics of coherences of different orders present in a system of two coupled nuclear spins. We used a previously designed model for intrinsic noise present in such systems which considers the Lindblad master equation for Markovian relaxation. We experimentally created zero-, single- and double-quantum coherences in several two-spin systems and performed a complete state tomography and computed state fidelity. We experimentally measured the decay of zero- and double-quantum coherences in these systems. The experimental data fitted well to a model that considers the main noise channels to be a correlated phase damping (CPD) channel acting simultaneously on both spins in conjunction with a generalised amplitude damping channel acting independently on both spins. The differential relaxation of multiple-quantum coherences can be ascribed to the action of a CPD channel acting simultaneously on both the spins. Keywords. Nuclear magnetic resonance relaxation theory; Multiple quantum coherences; Lindblad master equation; Markovian noisy channels. -
Arxiv:1611.07995V1 [Quant-Ph] 23 Nov 2016
Factoring using 2n + 2 qubits with Toffoli based modular multiplication Thomas H¨aner∗ Station Q Quantum Architectures and Computation Group, Microsoft Research, Redmond, WA 98052, USA and Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland Martin Roettelery and Krysta M. Svorez Station Q Quantum Architectures and Computation Group, Microsoft Research, Redmond, WA 98052, USA We describe an implementation of Shor's quantum algorithm to factor n-bit integers using only 2n+2 qubits. In contrast to previous space-optimized implementations, ours features a purely Toffoli based modular multiplication circuit. The circuit depth and the overall gate count are in (n3) and (n3 log n), respectively. We thus achieve the same space and time costs as TakahashiO et al. [1], Owhile using a purely classical modular multiplication circuit. As a consequence, our approach evades most of the cost overheads originating from rotation synthesis and enables testing and localization of faults in both, the logical level circuit and an actual quantum hardware implementation. Our new (in-place) constant-adder, which is used to construct the modular multiplication circuit, uses only dirty ancilla qubits and features a circuit size and depth in (n log n) and (n), respectively. O O I. INTRODUCTION Cuccaro [5] Takahashi [6] Draper [4] Our adder Size Θ(n) Θ(n) Θ(n2) Θ(n log n) Quantum computers offer an exponential speedup over Depth Θ(n) Θ(n) Θ(n) Θ(n) their classical counterparts for solving certain problems, n the most famous of which is Shor's algorithm [2] for fac- Ancillas n+1 (clean) n (clean) 0 2 (dirty) toring a large number N | an algorithm that enables the breaking of many popular encryption schemes including Table I. -
Arxiv:1701.02936V1 [Quant-Ph]
Lindbladian purification Christian Arenz,1, 2 Daniel Burgarth,1 Vittorio Giovannetti,3 Hiromichi Nakazato,4 and Kazuya Yuasa4 1Institute of Mathematics, Physics, and Computer Science, Aberystwyth University, Aberystwyth SY23 2BZ, UK 2Frick Laboratory, Princeton University, Princeton NJ 08544, US 3NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy 4Department of Physics, Waseda University, Tokyo 169-8555, Japan (Dated: September 16, 2018) In a recent work [D. K. Burgarth et al., Nat. Commun. 5, 5173 (2014)] it was shown that a series of frequent measurements can project the dynamics of a quantum system onto a subspace in which the dynamics can be more complex. In this subspace even full controllability can be achieved, although the controllability over the system before the projection is very poor since the control Hamiltonians commute with each other. We can also think of the opposite: any Hamiltonians of a quantum system, which are in general noncommutative with each other, can be made commutative by embedding them in an extended Hilbert space, and thus the dynamics in the extended space becomes trivial and simple. This idea of making noncommutative Hamiltonians commutative is called “Hamiltonian purification.” The original noncommutative Hamiltonians are recovered by projecting the system back onto the original Hilbert space through frequent measurements. Here we generalize this idea to open-system dynamics by presenting a simple construction to make Lindbladians, as well as Hamiltonians, commutative on a larger space with an auxiliary system. We show that the original dynamics can be recovered through frequently measuring the auxiliary system in a non-selective way. -
Efficient Quantum Algorithms for Simulating Lindblad Evolution
Efficient Quantum Algorithms for Simulating Lindblad Evolution∗† Richard Cleve1 and Chunhao Wang2 1 Institute for Quantum Computing, University of Waterloo, Waterloo, Canada; and Cheriton School of Computer Science, University of Waterloo, Waterloo, Canada; and Canadian Institute for Advanced Research, Toronto, Canada [email protected] 2 Institute for Quantum Computing, University of Waterloo, Waterloo, Canada; and Cheriton School of Computer Science, University of Waterloo, Canada [email protected] Abstract We consider the natural generalization of the Schrödinger equation to Markovian open system dynamics: the so-called the Lindblad equation. We give a quantum algorithm for simulating the evolution of an n-qubit system for time t within precision . If the Lindbladian consists of poly(n) operators that can each be expressed as a linear combination of poly(n) tensor products of Pauli operators then the gate cost of our algorithm is O(t polylog(t/)poly(n)). We also obtain similar bounds for the cases where the Lindbladian consists of local operators, and where the Lindbladian consists of sparse operators. This is remarkable in light of evidence that we provide indicating that the above efficiency is impossible to attain by first expressing Lindblad evolution as Schrödinger evolution on a larger system and tracing out the ancillary system: the cost of such a reduction incurs an efficiency overhead of O(t2/) even before the Hamiltonian evolution simulation begins. Instead, the approach of our algorithm is to use a novel variation of the “linear combinations of unitaries” construction that pertains to channels. 1998 ACM Subject Classification F.1.1 Models of Computation Keywords and phrases Quantum algorithms, open quantum systems, Lindblad simulation Digital Object Identifier 10.4230/LIPIcs.ICALP.2017.17 1 Introduction The problem of simulating the evolution of closed systems (captured by the Schrödinger equation) was proposed by Feynman [12] in 1982 as a motivation for building quantum computers. -
Hamiltonian Simulation with Nearly Optimal Dependence on All Parameters
Hamiltonian simulation with nearly optimal dependence on all parameters Dominic W. Berry∗ Andrew M. Childsy Robin Kothariz We present an algorithm for sparse Hamiltonian simulation that has optimal dependence on all pa- rameters of interest (up to log factors). Previous algorithms had optimal or near-optimal scaling in some parameters at the cost of poor scaling in others. Hamiltonian simulation via quantum walk has optimal dependence on the sparsity d at the expense of poor scaling in the allowed error . In contrast, an ap- proach based on fractional-query simulation provides optimal scaling in at the expense of poor scaling in d. Here we combine the two approaches, achieving the best features of both. By implementing a linear combination of quantum walk steps with coefficients given by Bessel functions, our algorithm achieves near-linear scaling in τ := dkHkmaxt and sublogarithmic scaling in 1/. Our dependence on is optimal, and we prove a new lower bound ruling out sublinear dependence on τ. The problem of simulating the dynamics of quantum systems was the original motivation for quantum com- puters [14] and remains one of their major potential applications. The first explicit quantum simulation algorithm [16] gave a method for simulating Hamiltonians that are sums of local interaction terms. Aharonov and Ta-Shma gave an efficient simulation algorithm for the more general class of sparse Hamiltonians [2], and much subsequent work has given improved simulations [4,5,6,7,8, 12, 17, 18]. Sparse Hamiltonians include most physically realistic Hamiltonians as a special case. In addition, sparse Hamiltonian simulation can also be used to design other quantum algorithms [9, 10, 15]. -
Quantum Computing: Lecture Notes
Quantum Computing: Lecture Notes Ronald de Wolf Preface These lecture notes were formed in small chunks during my “Quantum computing” course at the University of Amsterdam, Feb-May 2011, and compiled into one text thereafter. Each chapter was covered in a lecture of 2 45 minutes, with an additional 45-minute lecture for exercises and × homework. The first half of the course (Chapters 1–7) covers quantum algorithms, the second half covers quantum complexity (Chapters 8–9), stuff involving Alice and Bob (Chapters 10–13), and error-correction (Chapter 14). A 15th lecture about physical implementations and general outlook was more sketchy, and I didn’t write lecture notes for it. These chapters may also be read as a general introduction to the area of quantum computation and information from the perspective of a theoretical computer scientist. While I made an effort to make the text self-contained and consistent, it may still be somewhat rough around the edges; I hope to continue polishing and adding to it. Comments & constructive criticism are very welcome, and can be sent to [email protected] Attribution and acknowledgements Most of the material in Chapters 1–6 comes from the first chapter of my PhD thesis [71], with a number of additions: the lower bound for Simon, the Fourier transform, the geometric explanation of Grover. Chapter 7 is newly written for these notes, inspired by Santha’s survey [62]. Chapters 8 and 9 are largely new as well. Section 3 of Chapter 8, and most of Chapter 10 are taken (with many changes) from my “quantum proofs” survey paper with Andy Drucker [28]. -
Existence, Uniqueness and Approximation for Stochastic Schrodinger Equation: the Poisson Case Clement Pellegrini
Existence, uniqueness and approximation for stochastic Schrodinger equation: the Poisson case Clement Pellegrini To cite this version: Clement Pellegrini. Existence, uniqueness and approximation for stochastic Schrodinger equation: the Poisson case. 2009. hal-00174357v2 HAL Id: hal-00174357 https://hal.archives-ouvertes.fr/hal-00174357v2 Preprint submitted on 6 Mar 2009 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Existence, Uniqueness and Approximation of a Stochastic Schr¨odinger Equation: the Poisson Case Cl´ement PELLEGRINI Institut C.Jordan Universit´eC.Bernard, lyon 1 21, av Claude Bernard 69622 Villeurbanne Cedex France e-mail: [email protected] March 6, 2009 Abstract In quantum physics, recent investigations deal with the so-called ”quantum trajec- tory” theory. Heuristic rules are usually used to give rise to “stochastic Schr¨odinger equations” which are stochastic differential equations of non-usual type describing the physical models. These equations pose tedious problems in terms of mathematical and physical justifications: notion of solution, existence, uniqueness... In this article, we concentrate on a particular case: the Poisson case. Random Measure theory is used in order to give rigorous sense to such equations. We prove existence and uniqueness of a solution for the associated stochastic equation.