Basic Concepts in Quantum Information As Well As Provide a Basic Introduction to Circuit QED
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Superdense Teleportation and Quantum Key Distribution for Space Applications
2015 IEEE International Conference on Space Optical Systems and Applications (ICSOS) Superdense Teleportation and Quantum Key Distribution for Space Applications Trent Graham, Christopher Zeitler, Joseph Chapman, Hamid Javadi Paul Kwiat Submillimeter Wave Advanced Technology Group Department of Physics Jet Propulsion Laboratory, University of Illinois at Urbana-Champaign California Institute of Technology Urbana, USA Pasadena, USA tgraham2@illinois. edu Herbert Bernstein Institute for Science & Interdisciplinary Studies & School of Natural Sciences Hampshire College Amherst, USA Abstract—The transfer of quantum information over long for long periods of time (as would be needed for large scale distances has long been a goal of quantum information science quantum repeaters) and cannot be amplified without and is required for many important quantum communication introducing error [ 6 ] and thus can be very difficult to and computing protocols. When these channels are lossy and distribute over large distances using conventional noisy, it is often impossible to directly transmit quantum states communication techniques. Despite current limitations, some between two distant parties. We use a new technique called quantum communication protocols have already been superdense teleportation to communicate quantum demonstrated over long-distances in terrestrial experiments. information deterministically with greatly reduced resources, Notably, quantum teleportation (a remote quantum state simplified measurements, and decreased classical transfer protocol), -
Superdense Coding Ch.4.4 No Cloning Ch.4.2
C/CS/PhysC191 SuperdenseCoding,NoCloning 9/15/07 Fall 2009 Lecture 6 1 Readings Benenti, Casati, and Strini: Superdense Coding Ch.4.4 No Cloning Ch.4.2 2 Superdense Coding Super dense coding is the less popular sibling of teleportation. It can actually be viewed as the process in reverse. The idea is to transmit two classical bits of information by only sending one quantum bit. The process starts out with an EPR pair that is shared between the sender (Alice) and receiver (Bob). ψ = 1 00 + 11 √2 The first qubit is Alice’s, the second is Bob’s. Alice wants to send a two bit message to Bob, e.g., 00, 01, 10, or 11. She first performs a single qubit operation on her qubit which transforms the EPR pair according to which message she wants to send: • for a message 00: Alice applies I (i.e., does nothing) • for a message 01: Alice applies X • for a message 10: Alice applies Z • for a message 11: Alice applies iY (i.e. both X and Z) + + + This transforms the EPR pair φ into the four Bell (EPR) states φ , φ − , ψ , and ψ− , respec- tively: 1 1 0 0 • 00: 1 00 + 11 1 00 + 11 = 1 0 1 √2 −→ √2 √2 0 1 0 0 1 1 • 01: 1 00 + 11 1 10 + 01 = 1 1 0 √2 −→ √2 √2 1 0 1 1 0 0 • 10: 1 00 + 11 1 00 11 = 1 0 1 √2 −→ √2 − √2 0 − 1 − C/CS/Phys C191, Fall 2009, Lecture 6 1 0 0 i 1 • 11: i − 1 00 + 11 1 01 10 = 1 i 0 √2 −→ √2 − √2 1 − 0 The key to super-dense coding is that these four Bell states are orthonormal and are hence distinguishable by a quantum measurement, in this case a two-qubit measurement made by Bob. -
Quantum Optics with Electrical Circuits: Strong Coupling Cavity QED
Quantum Optics with Electrical Circuits: Strong Coupling Cavity QED Experiment Theory Rob Schoelkopf Michel Devoret Andreas Wallraff Steven Girvin Alexandre Blais (Sherbrooke) David Schuster NSF/Keck Foundation Hannes Majer Jay Gambetta Center Luigi Frunzio Axel Andre R. Vijayaraghavan for K. Moon (Yonsei) Irfan Siddiqi Quantum Information Physics Terri Yu Michael Metcalfe Chad Rigetti Yale University R-S Huang (Ames Lab) Andrew Houck K. Sengupta (Toronto) Cliff Cheung (Harvard) Aash Clerk (McGill) 1 A Circuit Analog for Cavity QED 2g = vacuum Rabi freq. κ = cavity decay rate γ = “transverse” decay rate out cm 2.5 λ ~ transmissionL = line “cavity” E B DC + 5 µm 6 GHz in - ++ - 2 Blais et al., Phys. Rev. A 2004 10 µm The Chip for Circuit QED Nb No wires Si attached Al to qubit! Nb First coherent coupling of solid-state qubit to single photon: A. Wallraff, et al., Nature (London) 431, 162 (2004) Theory: Blais et al., Phys. Rev. A 69, 062320 (2004) 3 Advantages of 1d Cavity and Artificial Atom gd= iERMS / Vacuum fields: Transition dipole: mode volume10−63λ de~40,000 a0 ∼ 10dRydberg n=50 ERMS ~ 0.25 V/m cm ide .5 gu 2 ave λ ~ w L = R ≥ λ e abl l c xia coa R λ 5 µm Cooper-pair box “atom” 4 Resonator as Harmonic Oscillator 1122 L r C H =+()LI CV r 22L Φ ≡=LI coordinate flux ˆ † 1 V = momentum voltage Hacavity =+ωr ()a2 ˆ † VV=+RMS ()aa 11ˆ 2 ⎛⎞1 CV00= ⎜⎟ω 22⎝⎠2 ω VV= r ∼ 12− µ RMS 2C 5 The Artificial Atom non-dissipative ⇒ superconducting circuit element non-linear ⇒ Josephson tunnel junction 1nm +n(2e) -n(2e) SUPERCONDUCTING Anharmonic! -
BPA NEWS Board on Physics and Astronomy • National Research Council • Washington, DC • 202-334-3520 • [email protected] • June 1999
BPA NEWS Board on Physics and Astronomy • National Research Council • Washington, DC • 202-334-3520 • [email protected] • June 1999 scientists, and educators must address Materials in a New Era—1999 Solid State several issues: (1) Our science policy is Sciences Committee Forum Summary outdated. (2) The American public does not understand science and its practice. by Thomas P. Russell, Chair, Solid State Sciences Committee (3) Scientists are politically clueless. It is The 1999 Solid State Sciences Com- tists must operate, and the changing roles evident that our nation needs to improve mittee Forum, entitled “Materials in a of government laboratories, industry, and its science, mathematics, engineering, and New Era,” was held at the National academic institutions in promoting technology education; to develop a new Academy of Sciences in Washington, materials science. concise, coherent, and comprehensive D.C., on February 16-17, 1999. This science policy; and to make its scientists article is a summary of the discussions. A Unlocking Our Future socially responsible and politically aware. more detailed account of the forum Laura Rodriguez, a staff member in The report makes four major recommen- appears in Materials in a New Era: Pro- the office of Representative Vernon dations: ceedings of the 1999 Solid State Sciences Ehlers (R-MI), set the stage from a na- 1. Continue to push the boundaries of the Committee Forum, soon to be available tional perspective with the keynote pre- scientific frontier by supporting interdis- from the Board on Physics and As- sentation on the recently issued study ciplinary research, maintaining a bal- tronomy. The agenda for the forum Unlocking Our Future: Toward a New anced research portfolio, and funding appears on Page 5 of this newsletter. -
The Quantum Times
TThhee QQuuaannttuumm TTiimmeess APS Topical Group on Quantum Information, Concepts, and Computation autumn 2007 Volume 2, Number 3 Science Without Borders: Quantum Information in Iran This year the first International Iran Conference on Quantum Information (IICQI) – see http://iicqi.sharif.ir/ – was held at Kish Island in Iran 7-10 September 2007. The conference was sponsored by Sharif University of Technology and its affiliate Kish University, which was the local host of the conference, the Institute for Studies in Theoretical Physics and Mathematics (IPM), Hi-Tech Industries Center, Center for International Collaboration, Kish Free Zone Organization (KFZO) and The Center of Excellence In Complex System and Condensed Matter (CSCM). The high level of support was instrumental in supporting numerous foreign participants (one-quarter of the 98 registrants) and also in keeping the costs down for Iranian participants, and having the conference held at Kish Island meant that people from around the world could come without visas. The low cost for Iranians was important in making the Inside… conference a success. In contrast to typical conferences in most …you’ll find statements from of the world, Iranian faculty members and students do not have the candidates running for various much if any grant funding for conferences and travel and posts within our topical group. I therefore paid all or most of their own costs from their own extend my thanks and appreciation personal money, which meant that a low-cost meeting was to the candidates, who were under essential to encourage a high level of participation. On the plus a time-crunch, and Charles Bennett side, the attendees were extraordinarily committed to learning, and the rest of the Nominating discussing, and presenting work far beyond what I am used to at Committee for arranging the slate typical conferences: many participants came to talks prepared of candidates and collecting their and knowledgeable about the speaker's work, and the poster statements for the newsletter. -
Curriculum Vitae Steven M. Girvin
CURRICULUM VITAE STEVEN M. GIRVIN http://girvin.sites.yale.edu/ Mailing address: Courier Delivery: [email protected] Yale Quantum Institute Yale Quantum Institute (203) 432-5082 (office) PO Box 208 334 Suite 436, 17 Hillhouse Ave. (203) 240-7035 (cell) New Haven, CT 06520-8263 New Haven, CT 06511 USA EDUCATION: BS Physics (Magna Cum Laude) Bates College 1971 MS Physics University of Maine 1973 MS Physics Princeton University 1974 Ph.D. Physics Princeton University 1977 Thesis Supervisor: J.J. Hopfield Thesis Subject: Spin-exchange in the x-ray edge problem and many-body effects in the fluorescence spectrum of heavily-doped cadmium sulfide. Postdoctoral Advisor: G. D. Mahan HONORS, AWARDS AND FELLOWSHIPS: 2017 Hedersdoktor (Honoris Causus Doctorate), Chalmers University of Technology 2007 Fellow, American Association for the Advancement of Science 2007 Foreign Member, Royal Swedish Academy of Sciences 2007 Member, Connecticut Academy of Sciences 2007 Oliver E. Buckley Prize of the American Physical Society (with AH MacDonald and JP Eisenstein) 2006 Member, National Academy of Sciences 2005 Eugene Higgins Professorship in Physics, Yale University 2004 Fellow, American Academy of Arts and Sciences 2003 First recipient of Yale's Conde Award for Teaching Excellence in Physics, Applied Physics and Astronomy 1992 Distinguished Professor, Indiana University 1989 Fellow, American Physical Society 1983 Department of Commerce Bronze Medal for Superior Federal Service 1971{1974 National Science Foundation Graduate Fellow (University of Maine and Princeton University) 1971 Phi Beta Kappa (Bates College) 1968{1971 Charles M. Dana Scholar (Bates College) EMPLOYMENT: 2015-2017 Deputy Provost for Research, Yale University 2007-2015 Deputy Provost for Science and Technology, Yale University 2007 Assoc. -
Classical Information Capacity of Superdense Coding
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server Classical information capacity of superdense coding Garry Bowen∗ Department of Physics, Australian National University, Canberra, A.C.T. 0200, Australia. (February 1, 2001) Classical communication through quantum channels may be enhanced by sharing entanglement. Superdense coding allows the encoding, and transmission, of up to two classical bits of information in a single qubit. In this paper, the maximum classical channel capacity for states that are not maximally entangled is derived. Particular schemes are then shown to attain this capacity, firstly for pairs of qubits, and secondly for pairs of qutrits. 03.67.Hk Quantum information exhibits many features which do ters, then the maximal amount of classical information not have analogues in classical information theory [1]. that may be transferred is given by the Kholevo bound For this reason, when a quantum channel is used for com- [10], munication, there exist a number of different capacities for the different types of information transmitted through C = max S p (U k I )ρ (U k I )y k k A B AB A B the channel [2{5]. fU ;pkg ⊗ ⊗ A " k ! Superdense coding (referred to in this paper simply as X dense coding), first proposed by Bennett and Wiesner [6], k k y pkS (U IB )ρAB(U IB ) : (1) is where the transmission of classical information through − A ⊗ A ⊗ k # a quantum channel is enhanced by shared entanglement X between sender and receiver. The classical information This bound has been shown to be asymptotically attain- capacity for a channel where sender and receiver share able by using product state block coding [8,11]. -
General Overview of the Field
Introduction to quantum computing and simulability General overview of the field Daniel J. Brod Leandro Aolita Ernesto Galvão Outline: General overview of the field • What is quantum computing? • A bit of history; • The rules: the postulates of quantum mechanics; • Information-theoretic-flavoured consequences; • Entanglement; • No-cloning; • Teleportation; • Superdense coding; What is quantum computing? • Computing paradigm where information is processed with the rules of quantum mechanics. • Extremely interdisciplinary research area! • Physics, Computer science, Mathematics; • Engineering (the thing looks nice on paper, but building it is hard!); • Chemistry, biology and others (applications); • Promised speedup on certain computational problems; • New insights into foundations of quantum mechanics and computer science. Let’s begin with some history! Timeline of (classical) computing Charles Babbage Ada Lovelace (1791-1871) (1815-1852) Analytical Engine (1837) First computer program (1843) First proposed general purpose Written by Ada Lovelace for the mechanical computer. Not Analytical engine. Computes completed by lack of money ☹️ Bernoulli numbers. Timeline of (classical) computing Alonzo Church Alan Turing (1903-1995) (1912-1954) 1 0 1 0 0 1 1 0 1 Turing Machine (1936) World War II Abstract model for a universal Colossus, Bombe, Z3/Z4 and others; computing device. - Decryption of secret messages; - Ballistics; Timeline of (classical) computing Intel® 4004 (1971) 2.300 transistors. Intel® Core™ (2010) 560.000.000 transistors. Transistor -
The IBM Quantum Computing Platform
The IBM Quantum Computing Platform Martin Koppenh¨ofer https://www.quantumtheory-bruder.physik.unibas.ch/ Online resources https://www.quantumtheory-bruder.physik.unibas.ch/ people/martin-koppenhoefer/ quantum-computing-and-robotic-science-workshop.html installation guide material for this session slides 2 Outline 1 Recap Overview of quantum-computing platforms Bell states 2 Programming the quantum computer with python The qiskit framework Programming session 1 3 Superdense coding Programming session 2 4 Quantum algorithms Deutsch algorithm Programming session 3 3 Recap spins in large molecules + NMR ions in electromagnetic traps neutral atoms in optical lattices optical quantum computing 31P donor atoms in silicon electron spins in semiconductor quantum dots superconducting electrical circuits flux qubit * charge qubit phase qubit * transmon qubit topological qubits * online access 4 Recap Bell states 1 2 3 x H 1 jβ00i = p (j00i + j11i) |βxy > 2 CNOT 1 y jβ01i = p (j01i + j10i) 2 1 jβ10i = p (j00i − j11i) 1 input state: jxyi = j00i 2 2 apply Hadamard gate 1 jβ i = p (j01i − j10i) 1 1 11 H^ = p1 : 2 2 1 −1 p1 (j00i + j10i) General expression: 2 jβ i = p1 (j0yi + (−1)x j1¯yi) 3 apply CNOT gate: xy 2 p1 (j00i + j11i) = jβ i 2 00 5 Recap Bell states 6 Recap Bell states on a real quantum processor 7 Programming the quantum computer with python The qiskit framework 8 Programming the quantum computer with python The qiskit framework Terra Ignis define quantum algorithms characterize quantum by quantum circuits / pulses hardware adapt quantum -
Entanglement and Superdense Coding with Linear Optics
International Journal of Quantum Information Vol. 9, Nos. 7 & 8 (2011) 1737À1744 #.c World Scientific Publishing Company DOI: 10.1142/S0219749911008222 ENTANGLEMENT AND SUPERDENSE CODING WITH LINEAR OPTICS MLADEN PAVIČIĆ Chair of Physics, Faculty of Civil Engineering, University of Zagreb, Croatia [email protected] Received 16 May 2011 We discuss a scheme for a full superdense coding of entangled photon states employing only linear optics elements. By using the mixed basis consisting of four states that are unambigu- ously distinguishable by a standard and polarizing beam splitters we can deterministically transfer four messages by manipulating just one of the two entangled photons. The sender achieves the determinism of the transfer either by giving up the control over 50% of sent messages (although known to her) or by discarding 33% of incoming photons. Keywords: Superdense coding; quantum communication; Bell states; mixed basis. 1. Introduction Superdense coding (SC)1 — sending up to two bits of information, i.e. four messages, by manipulating just one of two entangled qubits (two-state quantum systems) — is considered to be a protocol that launched the field of quantum communication.2 Apart from showing how different quantum coding of information is from the classical one — which can encode only two messages in a two-state system — the protocol has also shown how important entanglement of qubits is for their manipulation. Such an entanglement has proven to be a genuine quantum effect that cannot be achieved with the help of two classical bit carriers because we cannot entangle classical systems. To use this advantage of quantum information transfer, it is very important to keep the trade-off of the increased transfer capacity balanced with the technology of implementing the protocol. -
Building an Interesting Quantum Computer…
Building an Interesting Quantum Computer… Rob Schoelkopf Applied Physics Yale University PI’s @ Yale: RS Michel Devoret Luigi Frunzio Steven Girvin Leonid Glazman Liang Jiang Postdocs & grad students wanted! Overview Where are “we” today? We will build (in next ~ 5 years) interesting quantum devices: = complexity that CANNOT EVER be classically simulated (> 50 qubits or equivalent) Now beginning a new era where a merger is needed: quantum device physics systems engineering “quantum computer science” information thy./algorithms Outstanding questions: what’s the best architecture? how much overhead for error correction (QEC)? who will be the first to build something useful ? Still lots of innovation in physics, engineering, and theory ahead! Classical vs. Quantum Bits Information as state of a two-level quantum system Classical bit Quantum bits (or “qubits”) single atom single spin values 0 or 1 (never in between!) g = 0 ↑=0 define: e = 1 ↓=1 superposition: Ψ=αβ01 + What’s so special about the quantum world? Part 1: Superposition “the twin-slit experiment” source of 1 interference particles pattern = quantum 0 coherence Classical objects go either one way or the other. Quantum objects (electrons, photons) go both ways. Gives a quantum computation an inherent kind of parallelism! What’s so special about the quantum world? Part 2: Entanglement, or when more is (exponentially) different! Start with N non-interacting qubits Ψ2 Ψ 1 Ψ N Ψ=tot (αβ1101 +) ⊗( αβ 2 01 + 2) ⊗ (αβNN01+ ) “Product” state (non-interacting) of N qubits: ~ N bits of info -
Arxiv:1712.05854V1 [Quant-Ph] 15 Dec 2017
Deterministic remote entanglement of superconducting circuits through microwave two-photon transitions P. Campagne-Ibarcq,1, ∗ E. Zalys-Geller, A. Narla, S. Shankar, P. Reinhold, L. Burkhart, C. Axline, W. Pfaff, L. Frunzio, R. J. Schoelkopf,1 and M. H. Devoret1, † 1Department of Applied Physics, Yale University (Dated: December 19, 2017) Large-scale quantum information processing networks will most probably require the entanglement of distant systems that do not interact directly. This can be done by performing entangling gates between standing information carriers, used as memories or local computational resources, and flying ones, acting as quantum buses. We report the deterministic entanglement of two remote transmon qubits by Raman stimulated emission and absorption of a traveling photon wavepacket. We achieve a Bell state fidelity of 73%, well explained by losses in the transmission line and decoherence of each qubit. INTRODUCTION to shuffle information between the nodes of a network. However, the natural emission and absorption temporal envelopes of two identical nodes do not match as one Entanglement, which Schroedinger described as “the is the time-reversed of the other. Following pioneering characteristic trait of quantum mechanics” [1], is instru- work in ion traps [15], many experiments in circuit-QED mental for quantum information science applications have sought to modulate in time the effective coupling such as quantum cryptography and all the known of the emitter to a transmission channel in order to pure-state quantum algorithms [2]. Two systems Alice shape the “pitched” wavepacket [16–20]. Indeed, a rising and Bob that do not interact directly can be entangled if exponential wavepacket could be efficiently absorbed they interact locally with a third traveling system acting [21–24] by the receiver.