12 research outputs found
Spectroscopy of elementary excitations from quench dynamics in a dipolar XY Rydberg simulator
We use a Rydberg quantum simulator to demonstrate a new form of spectroscopy,
called quench spectroscopy, which probes the low-energy excitations of a
many-body system. We illustrate the method on a two-dimensional simulation of
the spin-1/2 dipolar XY model. Through microscopic measurements of the spatial
spin correlation dynamics following a quench, we extract the dispersion
relation of the elementary excitations for both ferro- and anti-ferromagnetic
couplings. We observe qualitatively different behaviors between the two cases
that result from the long-range nature of the interactions, and the frustration
inherent in the antiferromagnet. In particular, the ferromagnet exhibits
elementary excitations behaving as linear spin waves. In the anti-ferromagnet,
spin waves appear to decay, suggesting the presence of strong nonlinearities.
Our demonstration highlights the importance of power-law interactions on the
excitation spectrum of a many-body system.Comment: Main text 6 pages with 4 figures ; Supplemental Material 12 pages and
10 figure
Scalable spin squeezing in a dipolar Rydberg atom array
The standard quantum limit bounds the precision of measurements that can be
achieved by ensembles of uncorrelated particles. Fundamentally, this limit
arises from the non-commuting nature of quantum mechanics, leading to the
presence of fluctuations often referred to as quantum projection noise. Quantum
metrology relies on the use of non-classical states of many-body systems in
order to enhance the precision of measurements beyond the standard quantum
limit. To do so, one can reshape the quantum projection noise -- a strategy
known as squeezing. In the context of many-body spin systems, one typically
utilizes all-to-all interactions (e.g. the one-axis twisting model) between the
constituents to generate the structured entanglement characteristic of spin
squeezing. Motivated by recent theoretical work, here we explore the prediction
that short-range interactions -- and in particular, the two-dimensional dipolar
XY model -- can also enable the realization of scalable spin squeezing. Working
with a dipolar Rydberg quantum simulator of up to 100 atoms, we demonstrate
that quench dynamics from a polarized initial state lead to spin squeezing that
improves with increasing system size up to a maximum of -3.5 dB (prior to
correcting for detection errors, or approximately -5 dB after correction).
Finally, we present two independent refinements: first, using a multistep
spin-squeezing protocol allows us to further enhance the squeezing by
approximately 1 dB, and second, leveraging Floquet engineering to realize
Heisenberg interactions, we demonstrate the ability to extend the lifetime of
the squeezed state by freezing its dynamics.Comment: 12 pages, 10 figure
Phenotypic heterogeneity and evolution of melanoma cells associated with targeted therapy resistance
Phenotypic plasticity is associated with non-genetic drug tolerance in several cancers. Such plasticity can arise from chromatin remodeling, transcriptomic reprogramming, and/or protein signaling rewiring, and is characterized as a cell state transition in response to molecular or physical perturbations. This, in turn, can confound interpretations of drug responses and resistance development. Using BRAF-mutant melanoma cell lines as the prototype, we report on a joint theoretical and experimental investigation of the cell-state transition dynamics associated with BRAF inhibitor drug tolerance. Thermodynamically motivated surprisal analysis of transcriptome data was used to treat the cell population as an entropy maximizing system under the influence of time-dependent constraints. This permits the extraction of an epigenetic potential landscape for drug-induced phenotypic evolution. Single-cell flow cytometry data of the same system were modeled with a modified Fokker-Planck-type kinetic model. The two approaches yield a consistent picture that accounts for the phenotypic heterogeneity observed over the course of drug tolerance development. The results reveal that, in certain plastic cancers, the population heterogeneity and evolution of cell phenotypes may be understood by accounting for the competing interactions of the epigenetic potential landscape and state-dependent cell proliferation. Accounting for such competition permits accurate, experimentally verifiable predictions that can potentially guide the design of effective treatment strategies
Continuous Symmetry Breaking in a Two-dimensional Rydberg Array
Spontaneous symmetry breaking underlies much of our classification of phases
of matter and their associated transitions. The nature of the underlying
symmetry being broken determines many of the qualitative properties of the
phase; this is illustrated by the case of discrete versus continuous symmetry
breaking. Indeed, in contrast to the discrete case, the breaking of a
continuous symmetry leads to the emergence of gapless Goldstone modes
controlling, for instance, the thermodynamic stability of the ordered phase.
Here, we realize a two-dimensional dipolar XY model -- which exhibits a
continuous spin-rotational symmetry -- utilizing a programmable Rydberg quantum
simulator. We demonstrate the adiabatic preparation of correlated
low-temperature states of both the XY ferromagnet and the XY antiferromagnet.
In the ferromagnetic case, we characterize the presence of long-range XY order,
a feature prohibited in the absence of long-range dipolar interaction. Our
exploration of the many-body physics of XY interactions complements recent
works utilizing the Rydberg-blockade mechanism to realize Ising-type
interactions exhibiting discrete spin rotation symmetry.Comment: 18 pages, 3 figures in main text, 9 figures in supplemental method
Continuous symmetry breaking in a two-dimensional Rydberg array
Spontaneous symmetry breaking underlies much of our classification of phases of matter and their associated transitions. The nature of the underlying symmetry being broken determines many of the qualitative properties of the phase; this is illustrated by the case of discrete versus continuous symmetry breaking. Indeed, in contrast to the discrete case, the breaking of a continuous symmetry leads to the emergence of gapless Goldstone modes controlling, for instance, the thermodynamic stability of the ordered phase. Here, we realize a two-dimensional dipolar XY model that shows a continuous spin-rotational symmetry using a programmable Rydberg quantum simulator. We demonstrate the adiabatic preparation of correlated low-temperature states of both the XY ferromagnet and the XY antiferromagnet. In the ferromagnetic case, we characterize the presence of a long-range XY order, a feature prohibited in the absence of long-range dipolar interaction. Our exploration of the many-body physics of XY interactions complements recent works using the Rydberg-blockade mechanism to realize Ising-type interactions showing discrete spin rotation symmetry.This work is supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 817482 (PASQuanS), the Agence Nationale de la Recherche (ANR, project nos. RYBOTIN and ANR-22-PETQ-0004, project QuBitAF) and the European Research Council (advanced grant no. 101018511-ATARAXIA). J.H. acknowledges support from the NSF OIA Convergence Accelerator programme under award number 2040549, and the Munich Quantum Valley, which is supported by the Bavarian state government with funds from the Hightech Agenda Bayern Plus. M.S. and A.M.L. acknowledge support by the Austrian Science Fund (FWF) through grant no. I 4548. D.B. acknowledges support from grant no. MCIN/AEI/10.13039/501100011033 (grant nos. RYC2018- 025348-I, PID2020-119667GA-I00 and European Union NextGenerationEU PRTR-C17.I1). M.P.Z. acknowledges support from the Department of the Environment (DOE) Early Career programme and the Alfred P. Sloan foundation. N.Y.Y. acknowledges support from the Army Research Office (ARO) (grant no. W911NF-21-1-0262), the AFOSR MURI programme (grant no. W911NF-20-1-0136), the David and Lucile Packard foundation, and the Alfred P. Sloan foundation. M.B. and V.L. acknowledge support from NSF QLCI programme (grant no. OMA-2016245). S.C. acknowledges support from the ARO through the MURI programme (grant no. W911NF-17-1-0323) and from the US DOE, Office of Science, Office of Advanced Scientific Computing Research, under the Accelerated Research in Quantum Computing programme.Peer reviewe
Magnetism in the two-dimensional dipolar XY model
Motivated by a recent experiment on a square-lattice Rydberg atom array
realizing a long-range dipolar XY model [Chen et al., Nature (2023)], we
numerically study the model's equilibrium properties. We obtain the phase
diagram, critical properties, entropies, variance of the magnetization, and
site-resolved correlation functions. We consider both ferromagnetic and
antiferromagnetic interactions and apply quantum Monte Carlo and
pseudo-Majorana functional renormalization group techniques, generalizing the
latter to a U(1) symmetric setting. Our simulations open the door to directly
performing many-body thermometry in dipolar Rydberg atom arrays. Moreover, our
results provide new insights into the experimental data, suggesting the
presence of intriguing quasi-equilibrium features, and motivating future
studies on the non-equilibrium dynamics of the system.Comment: 7+14 page
Portaria 081
Conceder a(o) professor(a) MUHAMAD SUBHI MAHMUD HASAN HUSEIN, lotado(a) no Colégio de Aplicação (CA/CED), afastamento em regime de tempo integral para cursar Doutorado no exterior
Spectroscopy of elementary excitations from quench dynamics in a dipolar XY Rydberg simulator
International audienceWe use a Rydberg quantum simulator to demonstrate a new form of spectroscopy, called quench spectroscopy, which probes the low-energy excitations of a many-body system. We illustrate the method on a two-dimensional simulation of the spin-1/2 dipolar XY model. Through microscopic measurements of the spatial spin correlation dynamics following a quench, we extract the dispersion relation of the elementary excitations for both ferro- and anti-ferromagnetic couplings. We observe qualitatively different behaviors between the two cases that result from the long-range nature of the interactions, and the frustration inherent in the antiferromagnet. In particular, the ferromagnet exhibits elementary excitations behaving as linear spin waves. In the anti-ferromagnet, spin waves appear to decay, suggesting the presence of strong nonlinearities. Our demonstration highlights the importance of power-law interactions on the excitation spectrum of a many-body system