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:2103.01772 · Physical review. D/Physical review. D.

Log to log-log crossover of entanglement in a (1+1) -dimensional massive scalar field

Parul Jain, S. Mahesh Chandran, S. Shankaranarayanan

Published Jun 9, 2021• 8 citations
arXivHTMLPDF

Abstract

We study three different measures of quantum correlations---entanglement spectrum, entanglement entropy, and logarithmic negativity---for a ($1+1$)-dimensional massive scalar field in a flat space-time. The entanglement spectrum for the discretized scalar field in the ground state indicates a crossover in the zero-mode regime, which is further substantiated by an analytical treatment of both entanglement entropy and logarithmic negativity. The exact nature of this crossover depends on the boundary conditions used---the leading order term switches from a log to log-log behavior for the periodic and Neumann boundary conditions. In contrast, for Dirichlet, it is the parameters within the leading log-log term that are switched. We show that this crossover manifests as a change in the behavior of the leading order divergent term for entanglement entropy and logarithmic negativity close to the zero-mode limit. We thus show that the two regimes have fundamentally different information content. Furthermore, an analysis of the ground-state fidelity shows us that the region between critical point $\mathrm{\ensuremath{\Lambda}}=0$ and the crossover point is dominated by zero-mode effects, featuring an explicit dependence on the IR cutoff of the system. For the reduced state of a single oscillator, we show that this crossover occurs in the region $Na{m}_{f}\ensuremath{\sim}\ensuremath{\mathcal{O}}(1)$.

DOI
10.1103/physrevd.103.125008

Related papers

Universal scaling of the logarithmic negativity in massive quantum field theory

Olivier Blondeau-Fournier, Olalla A. Castro-Alvaredo, Benjamin Doyon

Abstract We consider the logarithmic negativity, a measure of bipartite entanglement, in a general unitary 1 + 1-dimensional massive quantum field theory, not necessarily integrable. We compute the negativity between a finite region of length r and an adjacent semi-infinite region, and that between two semi-infinite regions separated by a distance r . We show that the former saturates to a finite value, and that the latter tends to zero, as . We show that in both cases, the leading corrections are exponential decays in r (described by modified Bessel functions) that are solely controlled by the mass spectrum of the model, independently of its scattering matrix. This implies that, like the entanglement entropy (EE), the logarithmic negativity displays a very high level of universality, allowing one to extract information about the mass spectrum. Further, a study of sub-leading terms shows that, unlike the EE, a large- r analysis of the negativity allows for the detection of bound states.

arXiv:1508.04026•Journal of Physics A Mathematical and Theoretical•Feb 9, 2016•56 citations

Entanglement content of quantum particle excitations. Part II. Disconnected regions and logarithmic negativity

Olalla A. Castro-Alvaredo, Cecilia De Fazio, Benjamin Doyon +1 more

Abstract In this paper we study the increment of the entanglement entropy and of the (replica) logarithmic negativity in a zero-density excited state of a free massive bosonic theory, compared to the ground state. This extends the work of two previous publications by the same authors. We consider the case of two disconnected regions and find that the change in the entanglement entropy depends only on the combined size of the regions and is independent of their connectivity. We subsequently generalize this result to any number of disconnected regions. For the replica negativity we find that its increment is a polynomial with integer coefficients depending only on the sizes of the two regions. The logarithmic negativity turns out to have a more complicated functional structure than its replica version, typically involving roots of polynomials on the sizes of the regions. We obtain our results by two methods already employed in previous work: from a qubit picture and by computing four-point functions of branch point twist fields in finite volume. We test our results against numerical simulations on a harmonic chain and find excellent agreement.

arXiv:1904.01035•Journal of High Energy Physics•Nov 1, 2019•37 citations

Signature of criticality in angular momentum resolved entanglement of scalar fields in d > 1

Mrinal Kanti Sarkar, Saranyo Moitra, Rajdeep Sensarma

The scaling of entanglement entropy with subsystem size fails to distinguish between the gapped and the gapless ground states of a scalar field theory in $d>1$ dimensions. We show that the scaling of the angular momentum resolved entanglement entropy ${S}_{\ensuremath{\ell}}$ with the subsystem radius $R$ can clearly distinguish between these states. For a massless theory with momentum cutoff $\mathrm{\ensuremath{\Lambda}}, {S}_{\ensuremath{\ell}}\ensuremath{\sim}ln\phantom{\rule{0.16em}{0ex}}[\mathrm{\ensuremath{\Lambda}}R/\ensuremath{\ell}]$ for $\mathrm{\ensuremath{\Lambda}}R\ensuremath{\gg}\ensuremath{\ell}$, while ${S}_{\ensuremath{\ell}}\ensuremath{\sim}{R}^{0}$ for the massive theory. In contrast, for a free Fermi gas with Fermi wave vector ${k}_{F}, {S}_{\ensuremath{\ell}}\ensuremath{\sim}ln\phantom{\rule{0.16em}{0ex}}[{k}_{F}R]$ for ${k}_{F}R\ensuremath{\gg}\ensuremath{\ell}$. We show how this leads to an ``area-log'' scaling of total entanglement entropy of fermions, while the extra factor of $\ensuremath{\ell}$ leads to a leading area law even for massless bosons. At finite temperatures, we find that there is a crossover in the scaling of ${S}_{\ensuremath{\ell}}$ from the $T=0$ logarithmic scaling to a high $T$ linear scaling ${S}_{\ensuremath{\ell}}\ensuremath{\sim}\ensuremath{\pi}TR/3$. The logarithmic scaling exists for larger subsystem sizes for larger values of $\ensuremath{\ell}$. We provide estimates of temperatures and subsystem sizes where this critical scaling can be seen in experiments on ultracold atoms.

Physical review. B./Physical review. B•Aug 13, 2024•2 citations

Logarithmic corrections to the entropy of scalar field in BTZ black hole spacetime

Dharm Veer Singh, Shobhit Sachan

The entanglement entropy correlates two quantum subsystems which are part of a larger system. A logarithmic divergence term present in the entanglement entropy is universal in nature and directly proportional to the conformal anomaly. We study this logarithmic divergence term of entropy for massive scalar field in [Formula: see text] dimensions by applying numerical techniques to entanglement entropy approach. This (2+1)-dimensional massive theory can be obtained from the (3+1)-dimensional massless scalar field via dimensional reduction. We also calculated mass corrections to entanglement entropy for scalar field. Finally, we observe that the area law contribution to the entanglement entropy is not affected by this mass term and the universal quantities depend upon the basic properties of the system.

arXiv:1412.7170•International Journal of Modern Physics D•Oct 14, 2016•7 citations

Linear response of entanglement entropy to $$ T\overline{T} $$ in massive QFTs

Shachar Ashkenazi, Soumangsu Chakraborty, Zhanyu Ma +1 more

Abstract We compute the leading correction to entanglement entropy in $$ T\overline{T} $$ T T ¯ deformed massive QFTs. We show that both for massive scalar and Dirac fermion, the leading order correction to the entanglement entropy of half space comes from the boundary of the entangling surface. For the case of massive scalar, the boundary term is finite while for massive fermion, it diverges logarithmically giving rise to an additional log-square divergence in the entanglement entropy.

arXiv:2302.06688•Journal of High Energy Physics•Apr 18, 2023•5 citations

Dynamical scaling symmetry and asymptotic quantum correlations for time-dependent scalar fields

S. Mahesh Chandran, S. Shankaranarayanan

In time-independent quantum systems, entanglement entropy possesses an inherent scaling symmetry that the energy of the system does not have. The symmetry also assures that entropy divergence can be associated with the zero modes. We generalize this symmetry to time-dependent systems all the way from a coupled harmonic oscillator with a time-dependent frequency, to quantum scalar fields with time-dependent mass. We show that such systems have dynamical scaling symmetry that leaves the evolution of various measures of quantum correlations invariant; entanglement entropy, GS fidelity, the Loschmidt echo, and circuit complexity. Using this symmetry, we show that several quantum correlations are related at late times when the system develops instabilities. We then quantify such instabilities in terms of scrambling time and Lyapunov exponents. The delayed onset of exponential decay of the Loschmidt echo is found to be determined by the largest inverted mode in the system. On the other hand, a zero mode retains information about the system for a considerably longer time, finally resulting in a power-law decay of the Loschmidt echo. We extend the analysis to time-dependent massive scalar fields in ($1+1$)-dimensions and discuss the implications of zero modes and inverted modes occurring in the system at late times. We explicitly show the entropy scaling oscillates between the area-law and volume-law for a scalar field with stable modes or zero modes. We then provide a qualitative discussion of the above effects for scalar fields in cosmological and black hole spacetimes.

arXiv:2205.13338•Physical review. D/Physical review. D.•Jan 5, 2023•11 citations
We study three different measures of quantum correlations---entanglement spectrum, entanglement entropy, and logarithmic negativity---for a (1+11+11+1)-dimensional massive scalar field in a flat space-time. The entanglement spectrum for the discretized scalar field in the ground state indicates a crossover in the zero-mode regime, which is further substantiated by an analytical treatment of both entanglement entropy and logarithmic negativity. The exact nature of this crossover depends on the boundary conditions used---the leading order term switches from a log to log-log behavior for the periodic and Neumann boundary conditions. In contrast, for Dirichlet, it is the parameters within the leading log-log term that are switched. We show that this crossover manifests as a change in the behavior of the leading order divergent term for entanglement entropy and logarithmic negativity close to the zero-mode limit. We thus show that the two regimes have fundamentally different information content. Furthermore, an analysis of the ground-state fidelity shows us that the region between critical point \ensuremathΛ=0\mathrm{\ensuremath{\Lambda}}=0\ensuremathΛ=0 and the crossover point is dominated by zero-mode effects, featuring an explicit dependence on the IR cutoff of the system. For the reduced state of a single oscillator, we show that this crossover occurs in the region Namf\ensuremath∼\ensuremathO(1)Na{m}_{f}\ensuremath{\sim}\ensuremath{\mathcal{O}}(1)Namf​\ensuremath∼\ensuremathO(1).
Abstract We consider the logarithmic negativity, a measure of bipartite entanglement, in a general unitary 1 + 1-dimensional massive quantum field theory, not necessarily integrable. We compute the negativity between a finite region of length r and an adjacent semi-infinite region, and that between two semi-infinite regions separated by a distance r . We show that the former saturates to a finite value, and that the latter tends to zero, as . We show that in both cases, the leading corrections are exponential decays in r (described by modified Bessel functions) that are solely controlled by the mass spectrum of the model, independently of its scattering matrix. This implies that, like the entanglement entropy (EE), the logarithmic negativity displays a very high level of universality, allowing one to extract information about the mass spectrum. Further, a study of sub-leading terms shows that, unlike the EE, a large- r analysis of the negativity allows for the detection of bound states.
Abstract In this paper we study the increment of the entanglement entropy and of the (replica) logarithmic negativity in a zero-density excited state of a free massive bosonic theory, compared to the ground state. This extends the work of two previous publications by the same authors. We consider the case of two disconnected regions and find that the change in the entanglement entropy depends only on the combined size of the regions and is independent of their connectivity. We subsequently generalize this result to any number of disconnected regions. For the replica negativity we find that its increment is a polynomial with integer coefficients depending only on the sizes of the two regions. The logarithmic negativity turns out to have a more complicated functional structure than its replica version, typically involving roots of polynomials on the sizes of the regions. We obtain our results by two methods already employed in previous work: from a qubit picture and by computing four-point functions of branch point twist fields in finite volume. We test our results against numerical simulations on a harmonic chain and find excellent agreement.
The scaling of entanglement entropy with subsystem size fails to distinguish between the gapped and the gapless ground states of a scalar field theory in d>1d>1d>1 dimensions. We show that the scaling of the angular momentum resolved entanglement entropy ${S}_{\ensuremath{\ell}}$ with the subsystem radius RRR can clearly distinguish between these states. For a massless theory with momentum cutoff $\mathrm{\ensuremath{\Lambda}}, {S}_{\ensuremath{\ell}}\ensuremath{\sim}ln\phantom{\rule{0.16em}{0ex}}[\mathrm{\ensuremath{\Lambda}}R/\ensuremath{\ell}]$ for $\mathrm{\ensuremath{\Lambda}}R\ensuremath{\gg}\ensuremath{\ell}$, while ${S}_{\ensuremath{\ell}}\ensuremath{\sim}{R}^{0}$ for the massive theory. In contrast, for a free Fermi gas with Fermi wave vector ${k}_{F}, {S}_{\ensuremath{\ell}}\ensuremath{\sim}ln\phantom{\rule{0.16em}{0ex}}[{k}_{F}R]$ for ${k}_{F}R\ensuremath{\gg}\ensuremath{\ell}$. We show how this leads to an ``area-log'' scaling of total entanglement entropy of fermions, while the extra factor of $\ensuremath{\ell}$ leads to a leading area law even for massless bosons. At finite temperatures, we find that there is a crossover in the scaling of ${S}_{\ensuremath{\ell}}$ from the T=0T=0T=0 logarithmic scaling to a high TTT linear scaling ${S}_{\ensuremath{\ell}}\ensuremath{\sim}\ensuremath{\pi}TR/3$. The logarithmic scaling exists for larger subsystem sizes for larger values of $\ensuremath{\ell}$. We provide estimates of temperatures and subsystem sizes where this critical scaling can be seen in experiments on ultracold atoms.
The entanglement entropy correlates two quantum subsystems which are part of a larger system. A logarithmic divergence term present in the entanglement entropy is universal in nature and directly proportional to the conformal anomaly. We study this logarithmic divergence term of entropy for massive scalar field in [Formula: see text] dimensions by applying numerical techniques to entanglement entropy approach. This (2+1)-dimensional massive theory can be obtained from the (3+1)-dimensional massless scalar field via dimensional reduction. We also calculated mass corrections to entanglement entropy for scalar field. Finally, we observe that the area law contribution to the entanglement entropy is not affected by this mass term and the universal quantities depend upon the basic properties of the system.
Linear response of entanglement entropy to TT‾ T\overline{T} TT in massive QFTs
Abstract We compute the leading correction to entanglement entropy in TT‾ T\overline{T} TT T T ¯ deformed massive QFTs. We show that both for massive scalar and Dirac fermion, the leading order correction to the entanglement entropy of half space comes from the boundary of the entangling surface. For the case of massive scalar, the boundary term is finite while for massive fermion, it diverges logarithmically giving rise to an additional log-square divergence in the entanglement entropy.
In time-independent quantum systems, entanglement entropy possesses an inherent scaling symmetry that the energy of the system does not have. The symmetry also assures that entropy divergence can be associated with the zero modes. We generalize this symmetry to time-dependent systems all the way from a coupled harmonic oscillator with a time-dependent frequency, to quantum scalar fields with time-dependent mass. We show that such systems have dynamical scaling symmetry that leaves the evolution of various measures of quantum correlations invariant; entanglement entropy, GS fidelity, the Loschmidt echo, and circuit complexity. Using this symmetry, we show that several quantum correlations are related at late times when the system develops instabilities. We then quantify such instabilities in terms of scrambling time and Lyapunov exponents. The delayed onset of exponential decay of the Loschmidt echo is found to be determined by the largest inverted mode in the system. On the other hand, a zero mode retains information about the system for a considerably longer time, finally resulting in a power-law decay of the Loschmidt echo. We extend the analysis to time-dependent massive scalar fields in (1+11+11+1)-dimensions and discuss the implications of zero modes and inverted modes occurring in the system at late times. We explicitly show the entropy scaling oscillates between the area-law and volume-law for a scalar field with stable modes or zero modes. We then provide a qualitative discussion of the above effects for scalar fields in cosmological and black hole spacetimes.