scholarly journals A Cryptographic Test of Quantumness and Certifiable Randomness from a Single Quantum Device

2021 ◽  
Vol 68 (5) ◽  
pp. 1-47
Author(s):  
Zvika Brakerski ◽  
Paul Christiano ◽  
Urmila Mahadev ◽  
Umesh Vazirani ◽  
Thomas Vidick
Keyword(s):  
Polynomial Time ◽  
Single Quantum ◽  
Quantum Devices ◽  
New Model ◽  
Quantum Device ◽  
Cryptographic Primitive ◽  
Learning With Errors

We consider a new model for the testing of untrusted quantum devices, consisting of a single polynomial time bounded quantum device interacting with a classical polynomial time verifier. In this model, we propose solutions to two tasks—a protocol for efficient classical verification that the untrusted device is “truly quantum” and a protocol for producing certifiable randomness from a single untrusted quantum device. Our solution relies on the existence of a new cryptographic primitive for constraining the power of an untrusted quantum device: post-quantum secure trapdoor claw-free functions that must satisfy an adaptive hardcore bit property. We show how to construct this primitive based on the hardness of the learning with errors (LWE) problem.

scholarly journals A divide-and-conquer algorithm for quantum state preparation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Israel F. Araujo ◽  
Daniel K. Park ◽  
Francesco Petruccione ◽  
Adenilton J. da Silva
Keyword(s):  
Computational Cost ◽  
Quantum Circuit ◽  
Divide And Conquer ◽  
Computational Time ◽  
Quantum Computers ◽  
Dimensional Vector ◽  
Quantum Devices ◽  
Divide And Conquer Algorithm ◽  
Quantum State Preparation ◽  
Quantum Device

AbstractAdvantages in several fields of research and industry are expected with the rise of quantum computers. However, the computational cost to load classical data in quantum computers can impose restrictions on possible quantum speedups. Known algorithms to create arbitrary quantum states require quantum circuits with depth O(N) to load an N-dimensional vector. Here, we show that it is possible to load an N-dimensional vector with exponential time advantage using a quantum circuit with polylogarithmic depth and entangled information in ancillary qubits. Results show that we can efficiently load data in quantum devices using a divide-and-conquer strategy to exchange computational time for space. We demonstrate a proof of concept on a real quantum device and present two applications for quantum machine learning. We expect that this new loading strategy allows the quantum speedup of tasks that require to load a significant volume of information to quantum devices.

scholarly journals Generation of elementary gates and Bell’s states using controlled adiabatic evolutions

2019 ◽  
Vol 17 (03) ◽  
pp. 1950020
Author(s):  
Abderrahim Benmachiche ◽  
Ali Sellami ◽  
Sherzod Turaev ◽  
Derradji Bahloul ◽  
Azeddine Messikh ◽  
...  
Keyword(s):  
Quantum Computation ◽  
Open Systems ◽  
Circuit Model ◽  
Quantum Gates ◽  
Single Quantum ◽  
New Model ◽  
Adiabatic Quantum Computation ◽  
Usual Quantum

Fundamental quantum gates can be implemented effectively using adiabatic quantum computation or circuit model. Recently, Hen combined the two approaches to introduce a new model called controlled adiabatic evolutions [I. Hen, Phys. Rev. A, 91(2) (2015) 022309]. This model was specifically designed to implement one and two-qubit controlled gates. Later, Santos extended Hen’s work to implement [Formula: see text]-qubit controlled gates [A. C. Santos and M. S. Sarandy, Sci. Rep., 5 (2015) 15775]. In this paper, we discuss the implementation of each of the usual quantum gates, as well as demonstrate the possibility of preparing Bell’s states using the controlled adiabatic evolutions approach. We conclude by presenting the fidelity results of implementing single quantum gates and Bell’s states in open systems.

scholarly journals Photostability and long-term preservation of a colloidal semiconductor-based single photon emitter in polymeric photonic structures

2019 ◽  
Vol 1 (8) ◽  
pp. 3225-3231 ◽  
Author(s):  
Thi Huong Au ◽  
Stéphanie Buil ◽  
Xavier Quélin ◽  
Jean-Pierre Hermier ◽  
Ngoc Diep Lai
Keyword(s):  
Polymer Matrix ◽  
Single Photon ◽  
Photon Emission ◽  
Single Quantum ◽  
Single Photon Emission ◽  
Quantum Devices ◽  
Protective Polymer ◽  
Single Quantum Dot ◽  
Long Term Preservation

By using a protective polymer matrix, the single photon emission of a single quantum dot becomes perfectly stable. This also opens an excellent accessibility to realisation of photonic quantum devices.

scholarly journals Development of Quantum Simulator for Emerging Nanoelectronics Devices

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Dinh Sy Hien
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Graphic User Interface ◽  
Quantum Devices ◽  
Tunneling Diode ◽  
Quantum Device ◽  
Current Voltage ◽  
Effect Transistor

We have developed NEMO-VN2, a new quantum device modeling tool that simulates a wide variety of quantum devices including the resonant tunneling diode, the single electron transistor, the molecular field effect transistor, the carbon nanotube field effect transistor, and the spin field effect transistor. In this work the nonequilibrium Green’s function is used to perform a comprehensive study of the emerging nanoelectronics devices. The program has been written by using graphic user interface of Matlab. NEMO-VN2 uses Matlab to solve Schrodinger equation to get current-voltage characteristics of quantum devices. In the paper, we present a short overview of the theoretical methodology using non-equilibrium Green’s function for modeling of various quantum devices and typical simulations used to illustrate the capabilities of the NEMO-VN2.

Wigner Function Simulations of Quantum Device-Circuit Interactions

2003 ◽  
Vol 13 (04) ◽  
pp. 1255-1286 ◽  
Author(s):  
H. L. GRUBIN ◽  
R. C. BUGGELN
Keyword(s):  
Wigner Function ◽  
Switching Time ◽  
Wigner Equation ◽  
Large Signal ◽  
Quantum Devices ◽  
Quantum Device ◽  
Device Properties

Issues associated with modeling of quantum devices within the framework of the transient Wigner equation are addressed. Of particular importance is the structure of the Wigner function, hysteresis, and device switching time, whose value is determined by the large signal device properties.

scholarly journals Lattice Based Mix Network for Location Privacy in Mobile System

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Kunwar Singh ◽  
C. Pandu Rangan ◽  
A. K. Banerjee
Keyword(s):  
Polynomial Time ◽  
Location Privacy ◽  
Quantum Computer ◽  
Quantum Algorithm ◽  
Public Key ◽  
Mobile System ◽  
The Public ◽  
Diffie Hellman ◽  
Cryptographic Primitive ◽  
Time Quantum

In 1981, David Chaum proposed a cryptographic primitive for privacy calledmix network(Mixnet). A mixnet is cryptographic construction that establishes anonymous communication channel through a set of servers. In 2004, Golle et al. proposed a new cryptographic primitive called universal reencryption which takes the input as encrypted messages under the public key of the recipients not the public key of the universal mixnet. In Eurocrypt 2010, Gentry, Halevi, and Vaikunthanathan presented a cryptosystem which is an additive homomorphic and a multiplicative homomorphic for only one multiplication. In MIST 2013, Singh et al. presented a lattice based universal reencryption scheme under learning with error (LWE) assumption. In this paper, we have improved Singh et al.’s scheme using Fairbrother’s idea. LWE is a lattice hard problem for which till now there is no polynomial time quantum algorithm. Wiangsripanawan et al. proposed a protocol for location privacy in mobile system using universal reencryption whose security is reducible to Decision Diffie-Hellman assumption. Once quantum computer becomes a reality, universal reencryption can be broken in polynomial time by Shor’s algorithm. In postquantum cryptography, our scheme can replace universal reencryption scheme used in Wiangsripanawan et al. scheme for location privacy in mobile system.

scholarly journals Efficiently measuring a quantum device using machine learning

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
D. T. Lennon ◽  
H. Moon ◽  
L. C. Camenzind ◽  
Liuqi Yu ◽  
D. M. Zumbühl ◽  
...  
Keyword(s):  
Machine Learning ◽  
Large Scale ◽  
Learning Algorithm ◽  
Quantum Computers ◽  
Quantum Devices ◽  
Full Resolution ◽  
Large Numbers ◽  
Quantum Device ◽  
On Chip ◽  
Combining Information

Abstract Scalable quantum technologies such as quantum computers will require very large numbers of quantum devices to be characterised and tuned. As the number of devices on chip increases, this task becomes ever more time-consuming, and will be intractable on a large scale without efficient automation. We present measurements on a quantum dot device performed by a machine learning algorithm in real time. The algorithm selects the most informative measurements to perform next by combining information theory with a probabilistic deep-generative model that can generate full-resolution reconstructions from scattered partial measurements. We demonstrate, for two different current map configurations that the algorithm outperforms standard grid scan techniques, reducing the number of measurements required by up to 4 times and the measurement time by 3.7 times. Our contribution goes beyond the use of machine learning for data search and analysis, and instead demonstrates the use of algorithms to automate measurements. This works lays the foundation for learning-based automated measurement of quantum devices.

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