scholarly journals Encoding Two-Qubit Logical States and Quantum Operations Using the Energy States of a Physical System

Technologies ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Dimitrios Ntalaperas ◽  
Nikos Konofaos
Keyword(s):  
Quantum Computer ◽  
Quantum Systems ◽  
Quantum States ◽  
Discrete Energy ◽  
Quantum Operations ◽  
Single Qubit ◽  
Use Of Resources ◽  
Energy States ◽  
Qubit Operations ◽  
Charge Degree

In this paper, we introduce a novel coding scheme, which allows single quantum systems to encode multi-qubit registers. This allows for more efficient use of resources and the economy in designing quantum systems. The scheme is based on the notion of encoding logical quantum states using the charge degree of freedom of the discrete energy spectrum that is formed by introducing impurities in a semiconductor material. We propose a mechanism of performing single qubit operations and controlled two-qubit operations, providing a mechanism for achieving these operations using appropriate pulses generated by Rabi oscillations. The above architecture is simulated using the Armonk single qubit quantum computer of IBM to encode two logical quantum states into the energy states of Armonk’s qubit and using custom pulses to perform one and two-qubit quantum operations.

Transformation of Quantum States in Quantum Computation

2011 ◽  
Vol 80-81 ◽  
pp. 276-278
Author(s):  
Jun Lu
Keyword(s):  
Quantum Computation ◽  
Quantum Computer ◽  
Building Blocks ◽  
Quantum Systems ◽  
Quantum States ◽  
Quantum Bits ◽  
Universal Family ◽  
Unitary Transformations ◽  
Elementary Building ◽  
Arbitrary Selection

Quantum computation is based on transformation of quantum states. Quantum bits are two-level quantum systems, and as the simplest elementary building blocks for a quantum computer, they provide a convenient labeling for pairs of states and their physical realizations. Closed quantum systems evolve unitarily as determined by their Hamiltonians, but to perform quantum computation one must be able to control the Hamiltonian to effect an arbitrary selection from a universal family of unitary transformations.

Single-qubit operations on the Kane quantum computer

2002 ◽  
Vol 13 (5) ◽  
pp. 570-575 ◽  
Author(s):  
C J Wellard ◽  
L C L Hollenberg ◽  
C I Pakes
Keyword(s):  
Quantum Computer ◽  
Single Qubit ◽  
Qubit Operations

scholarly journals Simulating molecules on a cloud-based 5-qubit IBM-Q universal quantum computer

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
S. Leontica ◽  
F. Tennie ◽  
T. Farrow
Keyword(s):  
Quantum System ◽  
Energy Transport ◽  
Quantum Computer ◽  
Complex Molecule ◽  
Dissipative System ◽  
Quantum Simulation ◽  
Quantum Systems ◽  
Molecular Structures ◽  
Unitary Evolution ◽  
Universal Quantum

AbstractSimulating the behaviour of complex quantum systems is impossible on classical supercomputers due to the exponential scaling of the number of quantum states with the number of particles in the simulated system. Quantum computers aim to break through this limit by using one quantum system to simulate another quantum system. Although in their infancy, they are a promising tool for applied fields seeking to simulate quantum interactions in complex atomic and molecular structures. Here, we show an efficient technique for transpiling the unitary evolution of quantum systems into the language of universal quantum computation using the IBM quantum computer and show that it is a viable tool for compiling near-term quantum simulation algorithms. We develop code that decomposes arbitrary 3-qubit gates and implement it in a quantum simulation first for a linear ordered chain to highlight the generality of the approach, and second, for a complex molecule. We choose the Fenna-Matthews-Olsen (FMO) photosynthetic protein because it has a well characterised Hamiltonian and presents a complex dissipative system coupled to a noisy environment that helps to improve the efficiency of energy transport. The method can be implemented in a broad range of molecular and other simulation settings.

On-site localization of excitations

2005 ◽  
Vol 5 (4&5) ◽  
pp. 335-349
Author(s):  
M.I. Dykman ◽  
L.F. Santos ◽  
M. Shapiro ◽  
F. .M. Izrailev
Keyword(s):  
Quantum Computer ◽  
Infinite Chain ◽  
Quantum Operations ◽  
Site Localization ◽  
Excitation State ◽  
Coupled Qubits

We demonstrate that, in a quantum computer with perpetually coupled qubits, all excitations can be confined to their sites (qubits) even without refocusing. The on-site localization is obtained by constructing a sequence of qubit energies that efficiently suppresses resonant hopping. The time during which a many-excitation state remains strongly localized in an infinite chain can exceed the reciprocal hopping frequency by $\agt 10^5$ already for a moderate bandwidth of qubit energies. The proposed energy sequence is also convenient for performing quantum operations on the qubits.

Simulation of n-qubit quantum systems. III. Quantum operations

2007 ◽  
Vol 176 (9-10) ◽  
pp. 617-633 ◽  
Author(s):  
T. Radtke ◽  
S. Fritzsche
Keyword(s):  
Quantum Systems ◽  
Quantum Operations

scholarly journals Two-dimensional semiconductors pave the way towards dopant-based quantum computing

2018 ◽  
Vol 9 ◽  
pp. 2668-2673 ◽  
Author(s):  
José Carlos Abadillo-Uriel ◽  
Belita Koiller ◽  
María José Calderón
Keyword(s):  
Conduction Band ◽  
Quantum Computer ◽  
2D Materials ◽  
Exchange Interactions ◽  
Lattice Parameter ◽  
Oscillatory Behavior ◽  
Conduction Band Edge ◽  
Two Dimensional ◽  
Tunnel Coupling ◽  
Qubit Operations

Since the proposal in 1998 to build a quantum computer using dopants in silicon as qubits, much progress has been made in the nanofabrication of semiconductors and the control of charge and spins in single dopants. However, an important problem remains unsolved, namely the control over exchange interactions and tunneling between two donors, which presents a peculiar oscillatory behavior as the dopants relative positions vary at the scale of the lattice parameter. Such behavior is due to the valley degeneracy in the conduction band of silicon, and does not occur when the conduction-band edge is at k = 0. We investigate the possibility of circumventing this problem by using two-dimensional (2D) materials as hosts. Dopants in 2D systems are more tightly bound and potentially easier to position and manipulate. Moreover, many of them present the conduction band minimum at k = 0, thus no exchange or tunnel coupling oscillations. Considering the properties of currently available 2D semiconductor materials, we access the feasibility of such a proposal in terms of quantum manipulability of isolated dopants (for single qubit operations) and dopant pairs (for two-qubit operations). Our results indicate that a wide variety of 2D materials may perform at least as well as, and possibly better, than the currently studied bulk host materials for donor qubits.

scholarly journals Multi-Bloch vector representation of the qutrit

2011 ◽  
Vol 11 (5&6) ◽  
pp. 361-373
Author(s):  
Pawel Kurzynski
Keyword(s):  
Quantum State ◽  
Quantum Systems ◽  
Quantum States ◽  
The Other ◽  
Two Dimensional ◽  
Bloch Vector ◽  
Vector Representation ◽  
Alternative Approach ◽  
Complete Set

An ability to describe quantum states directly by average values of measurement outcomes is provided by the Bloch vector. For an informationally complete set of measurements one can construct unique Bloch vector for any quantum state. However, not every Bloch vector corresponds to a quantum state. It seems that only for two-dimensional quantum systems it is easy to distinguish proper Bloch vectors from improper ones, i.e. the ones corresponding to quantum states from the other ones. I propose an alternative approach to the problem in which more than one vector is used. In particular, I show that a state of the qutrit can be described by the three qubit-like Bloch vectors.

What Is Light, Really?

2011 ◽  
Author(s):  
Sönke Johnsen
Keyword(s):  
Quantum Mechanics ◽  
Physical Properties ◽  
Quantum Entanglement ◽  
Uncertainty Principle ◽  
Modern Theory ◽  
Discrete Energy ◽  
Wave Particle Duality ◽  
The World ◽  
Energy States

This concluding chapter explains that the modern theory of light falls within the field of quantum mechanics. At first glance, quantum mechanics does not seem that strange—its name is based on the fact that light comes in units and that electrons have discrete energy states. It also includes the uncertainty principle, which states that one cannot know certain pairs of physical properties with perfect precision. Moreover, quantum mechanics involves the wave-particle duality of photons. The chapter then explores two of the most unusual aspects of quantum mechanics: two-slit interference and quantum entanglement. Both violate the most fundamental notions about how the world works.

Sign in / Sign up

Export Citation Format

Share Document