English
Related papers

Related papers: Non-Hermitian Computers Need No Complex Numbers

200 papers

We introduce group surface codes, which are a natural generalization of the $\mathbb{Z}_2$ surface code, and equivalent to quantum double models of finite groups with specific boundary conditions. We show that group surface codes can be…

Quantum Physics · Physics 2026-03-06 Naren Manjunath , Vieri Mattei , Apoorv Tiwari , Tyler D. Ellison

Manifestly non-Hermitian quantum graphs with real spectra are introduced and shown tractable as a new class of phenomenological models with several appealing descriptive properties. For illustrative purposes, just equilateral star-graphs…

High Energy Physics - Theory · Physics 2009-11-10 Miloslav Znojil

Non-Hermitian systems satisfying parity-time (PT) symmetry have aroused considerable interest owing to their exotic features. Anti-PT symmetry is an important counterpart of the PT symmetry, and has been studied in various classical…

Quantum Physics · Physics 2024-06-21 Ji Bian , Pengfei Lu , Teng Liu , Hao Wu , Xinxin Rao , Kunxu Wang , Qifeng Lao , Yang Liu , Feng Zhu , Le Luo

We define a model of quantum computation with local fermionic modes (LFMs) -- sites which can be either empty or occupied by a fermion. With the standard correspondence between the Foch space of $m$ LFMs and the Hilbert space of $m$ qubits,…

Quantum Physics · Physics 2009-11-06 Sergey Bravyi , Alexei Kitaev

Quantum computation with quantum data that can traverse closed timelike curves represents a new physical model of computation. We argue that a model of quantum computation in the presence of closed timelike curves can be formulated which…

Quantum Physics · Physics 2008-11-26 Dave Bacon

Understanding the boundary between classical simulatability and the power of quantum computation is a fascinating topic. Direct simulation of noisy quantum computation requires solving an open quantum many-body system, which is very costly.…

Quantum Physics · Physics 2018-10-09 Xun Gao , Luming Duan

Universal quantum computation using photonic systems requires gates whose Hamiltonians are of order greater than quadratic in the quadrature operators. We first review previous proposals to implement such gates, where specific non-Gaussian…

Quantum Physics · Physics 2018-06-26 Krishna Kumar Sabapathy , Christian Weedbrook

Simple constructions and protocols are demonstrated to allow the implementation of universal quantum computation on an arbitrarily large quantum system by controlling a fixed number of spins, vastly reducing the engineering requirements in…

Quantum Physics · Physics 2009-04-23 Alastair Kay

Quantum computing promises the ability to compute properties of quantum systems exponentially faster than classical computers. Quantum advantage is achieved when a practical problem is solved more efficiently on a quantum computer than on a…

Quantum Physics · Physics 2025-12-03 William A. Simon , Peter J. Love

Quantum computation offers a promising alternative to classical computing methods in many areas of numerical science, with algorithms that make use of the unique way in which quantum computers store and manipulate data often achieving…

Quantum Physics · Physics 2022-07-19 Christopher D. Phillips , Vladimir I. Okhmatovski

A non-Hermitian Hamiltonian that has an unbroken PT symmetry can be converted by means of a similarity transformation to a physically equivalent Hermitian Hamiltonian. This raises the following question: In which form of the quantum theory,…

High Energy Physics - Theory · Physics 2009-11-11 Carl M. Bender , Jun-Hua Chen , Kimball A. Milton

The nonadiabatic holonomic quantum computation based on the geometric phase is robust against the built-in noise and decoherence. In this work, we theoretically propose a scheme to realize nonadiabatic holonomic quantum gates in a surface…

Quantum Physics · Physics 2024-05-07 Jun Wang , Wan-Ting He , Hai-Bo Wang , Qing Ai

Non-unitary operations generated by an effective non-Hermitian Hamiltonian can be used to create quantum state manipulations which are impossible in Hermitian quantum mechanics. These operations include state preparation (or cooling) and…

Quantum Physics · Physics 2014-04-25 Raam Uzdin

The author analyzes quantum computation with the hybrid qubit (HQ) that is encoded using the three-electron configuration of a double quantum dot. All gate operations are controlled with electric signals, while the qubit remains at an…

Mesoscale and Nanoscale Physics · Physics 2015-07-14 Sebastian Mehl

A universal quantum computing scheme, with a universal set of logical gates, is proposed based on networks of 1D quantum systems. The encoding of information is in terms of universal features of gapped phases, for which effective field…

Quantum Physics · Physics 2019-07-24 Dong-Sheng Wang

Richard Feynman's observation that quantum mechanical effects could not be simulated efficiently on a computer led to speculation that computation in general could be done more efficiently if it used quantum effects. This speculation…

Quantum Physics · Physics 2010-01-05 Eleanor G. Rieffel , Wolfgang Polak

In the popular ${\cal PT}-$symmetry-based formulation of quantum mechanics of closed systems one can build unitary models using non-Hermitian Hamiltonians (i.e., $H \neq H^\dagger$) which are Hermitizable (so that one can write,…

Quantum Physics · Physics 2022-03-15 Miloslav Znojil

Many promising ideas for quantum computing demand the experimental ability to directly switch 'on' and 'off' a physical coupling between the component qubits. This is typically the key difficulty in implementation, and precludes quantum…

Quantum Physics · Physics 2009-11-07 Simon C. Benjamin , Sougato Bose

Bosonic quantum systems operate in an infinite-dimensional Hilbert space, unlike discrete-variable quantum systems. This distinct mathematical structure leads to fundamental differences in quantum information processing, such as an…

Quantum Physics · Physics 2025-09-05 Varun Upreti , Dorian Rudolph , Ulysse Chabaud

While quantum computers are expected to yield considerable advantages over classical devices, the precise features of quantum theory enabling these advantages remain unclear. Contextuality--the denial of a notion of classical physical…

Quantum Physics · Physics 2018-06-11 Nadish de Silva