Minimum optical depth multi-port interferometers for approximating any
unitary transformation and any pure state
- URL: http://arxiv.org/abs/2002.01371v4
- Date: Tue, 10 May 2022 19:20:44 GMT
- Title: Minimum optical depth multi-port interferometers for approximating any
unitary transformation and any pure state
- Authors: Luciano Pereira, Alejandro Rojas, Gustavo Ca\~nas, Gustavo Lima, Aldo
Delgado, and Ad\'an Cabello
- Abstract summary: We show that any pure state, in any dimension $d$, can be prepared with infidelity $le 10-15$ using multi-port interferometers.
The schemes in [Phys. Rev. Lett. textbf73, 58 (1994) and Optica text3, 1460, 1460, only achieves an infidelity in the order of $10-7$ for block-diagonal unitary transformations.
- Score: 52.77024349608834
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Reconfigurable devices capable to implement any unitary operation with a
given fidelity are crucial for photonic universal quantum computation, optical
neural networks, and boson sampling. Here, we address the problems of
approximating with a given infidelity any unitary operation and any pure state
using multi-port interferometers, which are of current interest due to the
recent availability of multi-core fiber integrated multi-port interferometers.
We show that any pure state, in any dimension $d$, can be prepared with
infidelity $\le 10^{-15}$ with $3$~layers of $d$-dimensional Fourier transforms
and $3$~layers of configurable phase shifters. In contrast, the schemes in
[Phys. Rev. Lett. \textbf{73}, 58 (1994) and Optica \textbf{3}, 1460 (2016)],
require optical depth $2(d-1)$. We also present numerical evidence that
$d+1$~layers of $d$-dimensional Fourier transforms and $d+2$~layers of
configurable phase shifters can produce any unitary with infidelity $\le
10^{-14}$, while the scheme in [Phys. Rev. Lett. \textbf{124}, 010501 (2020)]
only achieves an infidelity in the order of $10^{-7}$ for block-diagonal
unitary transformations
Related papers
- Polarisation-insensitive state preparation for trapped-ion hyperfine qubits [0.0]
Quantum state preparation for trapped-ion qubits often relies on high-quality circularly-polarised light.
We propose and implement a hybrid optical/microwave scheme for intermediate-field hyperfine qubits.
We find that the fidelity remains above $99.8%$ for a mixture of all polarisations.
arXiv Detail & Related papers (2024-06-20T16:11:37Z) - Distributed quantum multiparameter estimation with optimal local measurements [0.0]
We study a sensor made by an array of $d$ spatially-distributed Mach-Zehnder interferometers (MZIs)
We show that local measurements, independently performed on each MZI, are sufficient to provide a sensitivity saturating the quantum Cram'er-Rao bound.
We find that the $d$ independent interferometers can achieve the same sensitivity of the entangled protocol but at the cost of using additional $d$ non-classical states.
arXiv Detail & Related papers (2024-05-28T17:45:07Z) - Towards large-scale quantum optimization solvers with few qubits [59.63282173947468]
We introduce a variational quantum solver for optimizations over $m=mathcalO(nk)$ binary variables using only $n$ qubits, with tunable $k>1$.
We analytically prove that the specific qubit-efficient encoding brings in a super-polynomial mitigation of barren plateaus as a built-in feature.
arXiv Detail & Related papers (2024-01-17T18:59:38Z) - Exact zeros of fidelity in finite-size systems as a signature for
probing quantum phase transitions [4.889561507168047]
In general, the fidelity $mathcalF(gamma,tildegamma)$ always approaches zero in the thermodynamical limit.
We show that exact zero of fidelity can be always accessed by tuning the magnetic flux.
Our work provides a practicable way to detect quantum phase transition via the calculation of fidelity of finite-size systems.
arXiv Detail & Related papers (2023-10-18T13:25:14Z) - Transformers as Support Vector Machines [54.642793677472724]
We establish a formal equivalence between the optimization geometry of self-attention and a hard-margin SVM problem.
We characterize the implicit bias of 1-layer transformers optimized with gradient descent.
We believe these findings inspire the interpretation of transformers as a hierarchy of SVMs that separates and selects optimal tokens.
arXiv Detail & Related papers (2023-08-31T17:57:50Z) - Numerical analysis of a three-wave-mixing Josephson traveling-wave
parametric amplifier with engineered dispersion loadings [62.997667081978825]
Recently proposed Josephson traveling-wave parametric amplifier has great potential in achieving a gain of 20 dB and a flat bandwidth of at least 4 GHz.
We model the advanced JTWPA circuit with periodic modulation of the circuit parameters.
engineered dispersion loadings allow achieving sufficiently wide $3$ dB-bandwidth from $3$ GHz to $9$ GHz combined with a reasonably small ripple.
arXiv Detail & Related papers (2022-09-22T14:46:04Z) - Synthesizing a $\hat{\sigma}_z$ spin-dependent force for optical,
metastable, and ground state trapped-ion qubits [0.0]
A single bichromatic field near-resonant to a qubit transition is typically used for $hatsigma_x$ or $hatsigma_y$ Molmer-Sorensen type interactions in trapped ion systems.
It is also possible to synthesize a $hatsigma_z$ spin-dependent force by merely adjusting the beat-note frequency.
arXiv Detail & Related papers (2022-07-22T17:03:22Z) - High fidelity two-qubit gates on fluxoniums using a tunable coupler [47.187609203210705]
Superconducting fluxonium qubits provide a promising alternative to transmons on the path toward large-scale quantum computing.
A major challenge for multi-qubit fluxonium devices is the experimental demonstration of a scalable crosstalk-free multi-qubit architecture.
Here, we present a two-qubit fluxonium-based quantum processor with a tunable coupler element.
arXiv Detail & Related papers (2022-03-30T13:44:52Z) - Robust marginalization of baryonic effects for cosmological inference at
the field level [12.768056235837427]
We train neural networks to perform likelihood-free inference from $(25,h-1rm Mpc)2$ 2D maps containing the total mass surface density.
We show that the networks can extract information beyond one-point functions and power spectra from all resolved scales.
arXiv Detail & Related papers (2021-09-21T18:00:01Z) - Quantum anomalous Hall phase in synthetic bilayers via twistless
twistronics [58.720142291102135]
We propose quantum simulators of "twistronic-like" physics based on ultracold atoms and syntheticdimensions.
We show that our system exhibits topologicalband structures under appropriate conditions.
arXiv Detail & Related papers (2020-08-06T19:58:05Z)
This list is automatically generated from the titles and abstracts of the papers in this site.
This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.