English
Related papers

Related papers: Computing n-time correlation functions without anc…

200 papers

We propose a method for computing n-time correlation functions of arbitrary spinorial, fermionic, and bosonic operators, consisting of an efficient quantum algorithm that encodes these correlations in an initially added ancillary qubit for…

Quantum Physics · Physics 2014-07-15 J. S. Pedernales , R. Di Candia , I. L. Egusquiza , J. Casanova , E. Solano

We propose and demonstrate a unified hierarchical method to measure $n$-point correlation functions that can be applied to driven, dissipative, or otherwise open or non-equilibrium quantum systems. In this method, the time evolution of the…

Quantum Physics · Physics 2024-02-29 Lorenzo Del Re , Brian Rost , Michael Foss-Feig , A. F. Kemper , J. K. Freericks

Quantum computing gives direct access to the study of real-time dynamics of quantum many-body systems. In principle, it is possible to directly calculate non-equal-time correlation functions, from which one can detect interesting phenomena,…

Characterising multi-time quantum processes is essential for analysing temporally correlated noise and for designing effective control and mitigation strategies. A complete operational description through multi-time process tomography…

Quantum Physics · Physics 2026-04-03 Abhinash Kumar Roy , Varun Srivastava , Christina Giarmatzi , Alexei Gilchrist

The measurement of dynamic correlation functions of quantum systems is complicated by measurement backaction. To facilitate such measurements we introduce a protocol, based on weak ancilla--system couplings, that is applicable to arbitrary…

Quantum Physics · Physics 2017-08-23 Philipp Uhrich , Salvatore Castrignano , Hermann Uys , Michael Kastner

To overcome the fast oscillatory behavior of correlation functions for extracting scattering phase shift in real-time quantum simulations encountered in Ref.\cite{Guo:2026qkx}, we propose and test two solutions in the present work. One is…

Quantum Physics · Physics 2026-04-02 Peng Guo , Paul LeVan , Frank X. Lee , Yong Zhao

Many quantum algorithms rely on the measurement of complex quantum amplitudes. Standard approaches to obtain the phase information, such as the Hadamard test, give rise to large overheads due to the need for global controlled-unitary…

Quantum Physics · Physics 2024-05-29 Yilun Yang , Arthur Christianen , Mari Carmen Bañuls , Dominik S. Wild , J. Ignacio Cirac

Dynamical correlations reveal important out-of-equilibrium properties of the underlying quantum many-body system, yet they are notoriously difficult to measure in experiments. While measurement protocols for dynamical correlations based on…

Quantum Physics · Physics 2025-04-07 Pavel P. Popov , Kevin T. Geier , Valentin Kasper , Maciej Lewenstein , Philipp Hauke

We consider simulating the BCS Hamiltonian, a model of low temperature superconductivity, on a quantum computer. In particular we consider conducting the simulation on the qubus quantum computer, which uses a continuous variable ancilla to…

Quantum Physics · Physics 2011-11-08 Katherine L. Brown , Suvabrata De , Vivien M. Kendon , William J. Munro

In this paper, we describe and experimentally demonstrate an error detection scheme that does not employ ancilla qubits or mid-circuit measurements. This is achieved by expanding the Hilbert space where a single logical qubit is encoded…

Quantum Physics · Physics 2022-04-26 Nicolas J. Guerrero , David E. Weeks

There has been recent progress in understanding chaotic features in many-body quantum systems. Motivated by the scrambling of information in black holes, it has been suggested that the time dependence of out-of-time-ordered (OTO)…

Quantum Physics · Physics 2016-12-28 Guanyu Zhu , Mohammad Hafezi , Tarun Grover

Quantum computing is emerging as a new computational paradigm with the potential to transform several research fields, including quantum chemistry. However, current hardware limitations (including limited coherence times, gate infidelities,…

Coulomb blockade effects in capacitively coupled quantum dots can be utilized for constructing an N-qubit system with antiferromagnetic Ising interactions. Starting from the tunneling Hamiltonian, we theoretically show that the Hamiltonian…

Quantum Physics · Physics 2009-11-06 Tetsufumi Tanamoto

Despite the pristine abilities of analog quantum simulators to study quantum dynamics, possibilities to detect currents are sparse. Here, we propose a flexible non-invasive technique to measure currents in quantum many-body systems by…

Quantum Physics · Physics 2021-06-25 Kevin T. Geier , Janika Reichstetter , Philipp Hauke

We discuss monitoring the time evolution of an analog quantum simulator via a quantum non-demolition (QND) coupling to an auxiliary `clock' qubit. The QND variable of interest is the `energy' of the quantum many-body system, represented by…

Quantum Physics · Physics 2020-10-14 Denis V. Vasilyev , Andrey Grankin , Mikhail A. Baranov , Lukas M. Sieberer , Peter Zoller

This thesis offers novel strategies for the measurement of quantum correlations present in controllable quantum systems, as well as for a full-fledged implementation of the models of light-matter interaction through which these correlations…

Quantum Physics · Physics 2016-11-30 Julen S. Pedernales

We present the first NMR implementation of a scheme for selective and efficient quantum process tomography without ancilla. We generalize this scheme such that it can be implemented efficiently using only a set of measurements involving…

Quantum Physics · Physics 2018-02-09 Akshay Gaikwad , Diksha Rehal , Amandeep Singh , Arvind , Kavita Dorai

Enhancing the precision of measurements by harnessing entanglement is a long-sought goal in the field of quantum metrology. Yet attaining the best sensitivity allowed by quantum theory in the presence of noise is an outstanding challenge,…

We introduce a protocol for the fast simulation of $n$-dimensional quantum systems on $n$-qubit quantum computers with tunable couplings. A mapping is given between the control parameters of the quantum computer and the matrix elements of…

The quantum circuit model is the de-facto way of designing quantum algorithms. Yet any level of abstraction away from the underlying hardware incurs overhead. In the era of near-term, noisy, intermediate-scale quantum (NISQ) hardware with…

Quantum Physics · Physics 2021-08-27 Laura Clinton , Johannes Bausch , Toby Cubitt
‹ Prev 1 2 3 10 Next ›