Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1804.09237 · New Journal of Physics

Quantum probe spectroscopy for cold atomic systems

A Usui, Berislav Buča, Jordi Mur-Petit

Published Sep 25, 2018• 13 citations
arXivHTMLPDF

Abstract

We study a two-level impurity coupled locally to a quantum gas on an optical lattice.For statedependent interactions between the impurity and the gas, we show that its evolution encodes information on the local excitation spectrum of the gas at the coupling site.Based on this, we design a nondestructive method to probe the system's excitations in a broad range of energies by measuring the state of the probe using standard atom optics methods.We illustrate our findings with numerical simulations for quantum lattice systems, including realistic dephasing noise on the quantum probe, and discuss practical limits on the probe dephasing rate to fully resolve both regular and chaotic spectra.

DOI
10.1088/1367-2630/aae418

Related papers

Nondestructive selective probing of phononic excitations in a cold Bose gas using impurities

Dominik Hangleiter, Mark T. Mitchison, T. H. Johnson +3 more

We introduce a detector that selectively probes the phononic excitations of a cold Bose gas. The detector is composed of a single impurity atom confined by a double-well potential, where the two lowest eigenstates of the impurity form an effective probe qubit that is coupled to the phonons via density-density interactions with the bosons. The system is analogous to a two-level atom coupled to photons of the radiation field. We demonstrate that tracking the evolution of the qubit populations allows probing both thermal and coherent excitations in targeted phonon modes. The targeted modes are selected in both energy and momentum by adjusting the impurity's potential. We show how to use the detector to observe coherent density waves and to measure temperatures of the Bose gas down to the nanokelvin regime. We analyze how our scheme could be realized experimentally, including the possibility of using an array of multiple impurities to achieve greater precision from a single experimental run.

arXiv:1411.0688•Physical Review A•Jan 12, 2015•39 citations

Measuring correlations of cold-atom systems using multiple quantum probes

Michael Streif, Andreas Buchleitner, Dieter Jaksch +1 more

We present a nondestructive method to probe a complex quantum system using multiple-impurity atoms as quantum probes. Our protocol provides access to different equilibrium properties of the system by changing its coupling to the probes. In particular, we show that measurements with two probes reveal the system's nonlocal two-point density correlations, for probe-system contact interactions. We illustrate our findings with analytic and numerical calculations for the Bose-Hubbard model in the weakly and strongly interacting regimes, under conditions relevant to ongoing experiments in cold-atom systems.

arXiv:1610.02795•Physical Review A•Nov 28, 2016•40 citations

Injection spectroscopy of momentum state lattices

Sai Naga Manoj Paladugu, Tao Chen, Fangzhao Alex An +2 more

Abstract The energy spectrum of quantum systems contain a wealth of information about their underlying properties. Spectroscopic techniques, especially those with access to spatially resolved measurements, can be challenging to implement in real-space systems of cold atoms in optical lattices. Here we explore a technique for probing energy spectra in synthetic lattices that is analogous to scanning tunneling microscopy. Using one-dimensional synthetic lattices of coupled atomic momentum states, we explore this spectroscopic technique and observe qualitative agreement between the measured and simulated energy spectra for small two- and three-site lattices as well as a uniform many-site lattice. Finally, through simulations, we show that this technique should allow for the exploration of the topological bands and the fractal energy spectrum of the Hofstadter model as realized in synthetic lattices.

Communications Physics•Jan 20, 2024•9 citations

Momentum-resolved spectroscopy of a 1D superfluid using a single atomic impurity

F. Cosco, Massimo Borrelli, Francesco Plastina +1 more

We present a general and non-invasive probing scheme to perform full momentum-resolved spectroscopy of a cold atomic gas loaded into an optical lattice using a single quantum impurity. The protocol relies on weak collisional interactions and subsequent population measurements of the impurity. By tuning a few controllable external parameters the impurity-lattice interaction can be engineered, and using two sets of measurements, performed with the impurity in two different positions, the full dispersion relation of the superfluid phonons can be reliably extracted.

arXiv:1811.01939•Nov 5, 2018•0 citations

Detection of superfluid excitations via local quantum probing

F. Cosco, Massimo Borrelli, Francesco Plastina +1 more

We propose a general and non-destructive probing scheme to detect and characterize the superfluid excitation spectrum of cold atoms in optical lattices. The protocol relies on a local collisional interaction between an embedded impurity and the surrounding atomic ensemble. By tuning a few controllable external parameters the impurity-lattice interaction can be engineered and information regarding the dispersion relation of the superfluid phonons can be reliably extracted. We describe the general theory and provide an example to show its validity.

•Nov 3, 2015•0 citations

Microscopy of interacting quantum systems

M. Eric Tai

Ultracold quantum gases in optical lattices provide a rich experimental toolbox for simulating the physics of condensed matter systems. With atoms in the lattice playing the role of electrons or Cooper pairs in real materials, it is possible to experimentally realize condensed matter Hamiltonians in a controlled way. To realize the full potential of such quantum simulations, we leverage a quantum gas microscope which can spatially resolve the atoms in the optical lattice at the single site level and project arbitrary potential landscapes onto the atoms by combining the high resolution optics with static holographic masks or a spatial light modulator. The versatility of this system allows for a wide range of studies. In this thesis, we focus on three experiments that highlight the utility of a tunable platform and demonstrate the richness of physics that comes with interactions.\nIn the first, we observe on-site interparticle interactions introduce a non-linearity into the many-body energy spectrum of a harmonic oscillator. The excitation of a single atom into a higher band induces an energy shift in the excitation energy for the second atom, blockading the orbital excitation. We demonstrate a technique for deterministic number filtering based upon orbital excitation blockade. When applied to a high temperature Mott insulator, this number filtering realizes a form of algorithmic cooling, which can be used for initializing a large quantum register or creating low entropy initial states for many-body simulation.\nIn the second, we study the applicability of statistical physics in an isolated system governed by quantum mechanics. While the descriptive power of these two fields has been confirmed through repeated and varied empirical studies, their underlying axioms of entropy maximization and unitary evolution appear mutually exclusive. With our quantum gas microscope, we have the ability to probe local observables such as the on-site number statistics as well as measure the quantum mechanical purity through interference operations. With these capabilities, we are able to observe the local thermalization of a manifestly quantum mechanically pure many-body system.\nIn the last chapter, we report on the first cold atoms studies of an interacting system under an artificial gauge field. We consider the propagation of a pair of atoms in a $2\\times N$ ladder governed by the Harper-Hofstadter model. The eigenstates of this system include both scattering states, which can exhibit chiral propagation, and bound states. A superexchange energy shift in our initial state leads to imbalanced population in the two chiral scattering sectors, leading to chiral propagation dynamics. This effect is the result of both the presence of interactions and the artificial gauge fields. These two components are essential ingredients for fractional quantum Hall physics. Moreover, the dynamic tunable gauge field we develop and the control afforded by a quantum gas microscope make this platform well-suited for future studies in this regime.

•May 12, 2017•0 citations
We study a two-level impurity coupled locally to a quantum gas on an optical lattice.For statedependent interactions between the impurity and the gas, we show that its evolution encodes information on the local excitation spectrum of the gas at the coupling site.Based on this, we design a nondestructive method to probe the system's excitations in a broad range of energies by measuring the state of the probe using standard atom optics methods.We illustrate our findings with numerical simulations for quantum lattice systems, including realistic dephasing noise on the quantum probe, and discuss practical limits on the probe dephasing rate to fully resolve both regular and chaotic spectra.
We introduce a detector that selectively probes the phononic excitations of a cold Bose gas. The detector is composed of a single impurity atom confined by a double-well potential, where the two lowest eigenstates of the impurity form an effective probe qubit that is coupled to the phonons via density-density interactions with the bosons. The system is analogous to a two-level atom coupled to photons of the radiation field. We demonstrate that tracking the evolution of the qubit populations allows probing both thermal and coherent excitations in targeted phonon modes. The targeted modes are selected in both energy and momentum by adjusting the impurity's potential. We show how to use the detector to observe coherent density waves and to measure temperatures of the Bose gas down to the nanokelvin regime. We analyze how our scheme could be realized experimentally, including the possibility of using an array of multiple impurities to achieve greater precision from a single experimental run.
We present a nondestructive method to probe a complex quantum system using multiple-impurity atoms as quantum probes. Our protocol provides access to different equilibrium properties of the system by changing its coupling to the probes. In particular, we show that measurements with two probes reveal the system's nonlocal two-point density correlations, for probe-system contact interactions. We illustrate our findings with analytic and numerical calculations for the Bose-Hubbard model in the weakly and strongly interacting regimes, under conditions relevant to ongoing experiments in cold-atom systems.
Abstract The energy spectrum of quantum systems contain a wealth of information about their underlying properties. Spectroscopic techniques, especially those with access to spatially resolved measurements, can be challenging to implement in real-space systems of cold atoms in optical lattices. Here we explore a technique for probing energy spectra in synthetic lattices that is analogous to scanning tunneling microscopy. Using one-dimensional synthetic lattices of coupled atomic momentum states, we explore this spectroscopic technique and observe qualitative agreement between the measured and simulated energy spectra for small two- and three-site lattices as well as a uniform many-site lattice. Finally, through simulations, we show that this technique should allow for the exploration of the topological bands and the fractal energy spectrum of the Hofstadter model as realized in synthetic lattices.
We present a general and non-invasive probing scheme to perform full momentum-resolved spectroscopy of a cold atomic gas loaded into an optical lattice using a single quantum impurity. The protocol relies on weak collisional interactions and subsequent population measurements of the impurity. By tuning a few controllable external parameters the impurity-lattice interaction can be engineered, and using two sets of measurements, performed with the impurity in two different positions, the full dispersion relation of the superfluid phonons can be reliably extracted.
We propose a general and non-destructive probing scheme to detect and characterize the superfluid excitation spectrum of cold atoms in optical lattices. The protocol relies on a local collisional interaction between an embedded impurity and the surrounding atomic ensemble. By tuning a few controllable external parameters the impurity-lattice interaction can be engineered and information regarding the dispersion relation of the superfluid phonons can be reliably extracted. We describe the general theory and provide an example to show its validity.
Ultracold quantum gases in optical lattices provide a rich experimental toolbox for simulating the physics of condensed matter systems. With atoms in the lattice playing the role of electrons or Cooper pairs in real materials, it is possible to experimentally realize condensed matter Hamiltonians in a controlled way. To realize the full potential of such quantum simulations, we leverage a quantum gas microscope which can spatially resolve the atoms in the optical lattice at the single site level and project arbitrary potential landscapes onto the atoms by combining the high resolution optics with static holographic masks or a spatial light modulator. The versatility of this system allows for a wide range of studies. In this thesis, we focus on three experiments that highlight the utility of a tunable platform and demonstrate the richness of physics that comes with interactions.\nIn the first, we observe on-site interparticle interactions introduce a non-linearity into the many-body energy spectrum of a harmonic oscillator. The excitation of a single atom into a higher band induces an energy shift in the excitation energy for the second atom, blockading the orbital excitation. We demonstrate a technique for deterministic number filtering based upon orbital excitation blockade. When applied to a high temperature Mott insulator, this number filtering realizes a form of algorithmic cooling, which can be used for initializing a large quantum register or creating low entropy initial states for many-body simulation.\nIn the second, we study the applicability of statistical physics in an isolated system governed by quantum mechanics. While the descriptive power of these two fields has been confirmed through repeated and varied empirical studies, their underlying axioms of entropy maximization and unitary evolution appear mutually exclusive. With our quantum gas microscope, we have the ability to probe local observables such as the on-site number statistics as well as measure the quantum mechanical purity through interference operations. With these capabilities, we are able to observe the local thermalization of a manifestly quantum mechanically pure many-body system.\nIn the last chapter, we report on the first cold atoms studies of an interacting system under an artificial gauge field. We consider the propagation of a pair of atoms in a 2timesN2\\times N2timesN ladder governed by the Harper-Hofstadter model. The eigenstates of this system include both scattering states, which can exhibit chiral propagation, and bound states. A superexchange energy shift in our initial state leads to imbalanced population in the two chiral scattering sectors, leading to chiral propagation dynamics. This effect is the result of both the presence of interactions and the artificial gauge fields. These two components are essential ingredients for fractional quantum Hall physics. Moreover, the dynamic tunable gauge field we develop and the control afforded by a quantum gas microscope make this platform well-suited for future studies in this regime.