In-Saeng Suh - Academia.edu (original) (raw)

Papers by In-Saeng Suh

Cornell University - arXiv, Oct 29, 2022

The Poisson equation has many applications across the broad areas of science and engineering. Mos... more The Poisson equation has many applications across the broad areas of science and engineering. Most quantum algorithms for the Poisson solver presented so far either suffer from lack of accuracy and/or are limited to very small sizes of the problem, and thus have no practical usage. Here we present an advanced quantum algorithm for solving the Poisson equation with high accuracy and dynamically tunable problem size. After converting the Poisson equation to a linear system through the finite difference method, we adopt the HHL algorithm as the basic framework. Particularly, in this work we present an advanced circuit that ensures the accuracy of the solution by implementing non-truncated eigenvalues through eigenvalue amplification, as well as by increasing the accuracy of the controlled rotation angular coefficients, which are the critical factors in the HHL algorithm. Consequently, we are able to drastically reduce the relative error in the solution while achieving higher success probability as the amplification level is increased. We show that our algorithm not only increases the accuracy of the solutions but also composes more practical and scalable circuits by dynamically controlling problem size in NISQ devices. We present both simulated and experimental results and discuss the sources of errors. Finally, we conclude that though overall results on the existing NISQ hardware are dominated by the error in the CNOT gates, this work opens a path to realizing a multidimensional Poisson solver on near-term quantum hardware.

Cornell University - arXiv, Sep 19, 2022

The Poisson equation has many applications across the broad areas of science and engineering. Mos... more The Poisson equation has many applications across the broad areas of science and engineering. Most quantum algorithms for the Poisson solver presented so far, either suffer from lack of accuracy and/or are limited to very small sizes of the problem, and thus have no practical usage. Here we present an advanced quantum algorithm for solving the Poisson equation with high accuracy and dynamically tunable problem size. After converting the Poisson equation to the linear systems through the finite difference method, we adopt the Harrow-Hassidim-Lloyd (HHL) algorithm as the basic framework. Particularly, in this work we present an advanced circuit that ensures the accuracy of the solution by implementing non-truncated eigenvalues through eigenvalue amplification as well as by increasing the accuracy of the controlled rotation angular coefficients, which are the critical factors in the HHL algorithm. We show that our algorithm not only increases the accuracy of the solutions, but also composes more practical and scalable circuits by dynamically controlling problem size in the NISQ devices. We present both simulated and experimental solutions, and conclude that overall results on the quantum hardware are dominated by the error in the CNOT gates.

American Astronomical Society Meeting Abstracts, Jun 1, 2013

Bulletin of the American Physical Society, Apr 20, 2021

The Astrophysical Journal, 2022

The nuclear equation of state (EOS) is an important component in the evolution of core-collapse s... more The nuclear equation of state (EOS) is an important component in the evolution of core-collapse supernovae. In this paper we make a survey of various EOSs in the literature and analyze their effect on spherical core-collapse models in which the effects of three-dimensional turbulence is modeled by a general relativistic formulation of Supernova Turbulence In Reduced-dimensionality (STIR). We show that the viability of the explosion is quite EOS dependent and that it best correlates with the early-time interior entropy density of the proto–neutron star. We check that this result is not progenitor dependent, although the lowest-mass progenitors show different explosion properties, due to the different pre-collapse nuclear composition. Larger central entropies also induce more vigorous proto–neutron star convection in our one-dimensional turbulence model, as well as a wider convective layer.

The Eleventh Marcel Grossmann Meeting - On Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relativistic Field Theories - Proceedings of the MG11 Meeting on General Relativity, 2008

We summarize masses and radii for a number of white dwarfs as deduced from a combination of prope... more We summarize masses and radii for a number of white dwarfs as deduced from a combination of proper motion studies, Hipparcos parallax distances, effective temperatures, and binary or spectroscopic masses. A puzzling feature of these data, however, is that some stars appear to have radii which are significantly smaller than that expected for a standard electron-degenerate white-dwarf equations of state.

2022 IEEE International Conference on Quantum Computing and Engineering (QCE)

The Fifteenth Marcel Grossmann Meeting

The first detection of gravitational waves a binary neutron star merger GW170817 by the LIGO-Virg... more The first detection of gravitational waves a binary neutron star merger GW170817 by the LIGO-Virgo Collaboration has provided fundamental new insights into the astrophysical site for the r process nucleosynthesis and on the nature of dense neutron-star matter. The detected gravitational wave signal depends upon the tidal distortion of the neutron stars as they approach merger. We examine how the detected "chirp" depends the adopted equation of state. This places new constrains on the properties of nuclear matter. The detected evidence of heavy-element nucleosynthesis also provides insight into the nature of the r-process and the fission properties of the heaviest nuclei. Parametrically, one can divide models for the r-process into three scenarios roughly characterized by the number of neutron captures per seed nucleus (n/s). In addition to neutron-star mergers, these include magneto-hydrodynamic jets from supernovae and the neutrino heated wind above the proto neutron star in core-collapse supernovae. Insight from GW170817 allows one to better quantify the relative contributions of each astrophysical site and the fission termination of the r-process.

EPJ Web of Conferences, 2022

With observations of gravitational wave signals from binary neutron star mergers (BNSM) by LIGO-V... more With observations of gravitational wave signals from binary neutron star mergers (BNSM) by LIGO-Virgo-KAGRA (LVK) Collaboration and NICER, the nuclear equation of state (EOS) is becoming increasingly testable by complementary numerical simulations. Numerous simulations currently explore the EOS at different density regimes for the constituent neutron stars specifically narrowing the uncertainty in the sub-nuclear densities. In this paper we summarize the three-dimensional general relativistic-hydrodynamics based simulations of BNSMs for EOSs with a specific emphasis on the quark matter EOS at the highest densities.

arXiv: General Relativity and Quantum Cosmology, 2016

We study the general relativistic hydrodynamic evolution of neutron stars in binary orbits and an... more We study the general relativistic hydrodynamic evolution of neutron stars in binary orbits and analyze the equation of state dependence of the orbits as the stars approach the inner most last stable circular orbit. We show that by employing a conformally flat condition on the metric, one can stably numerically evolve ~100 quasi-circular orbits and could straightforwardly extend the calculation to the ~10,000 orbits needed to follow stars through the LIGO frequency band. We apply this code to orbiting neutron stars in the quasi-circular orbit approximation to both demonstrate the stability of this approach and explore the equation of state dependence of the orbital properties. We employ variety of available realistic neutron star equations of state as well as a Gamma=2 polytrope. We confirm that both the orbital and emergent gravity wave frequency evolve more slowly for a softer equation of state as the stars approach the innermost stable circular orbit.

Recently, neutron stars with very strong surface magnetic fi lds have been suggested as the site ... more Recently, neutron stars with very strong surface magnetic fi lds have been suggested as the site for the origin of observed soft gamma repeaters (SGRs). In this paper we inv est gate the influence of such strong magnetic fields on the properties and internal structure of these magn etized neutron stars (magnetars). We study properties of a degenerate equilibrium ideal neutron-proton-electro n (npe) gas model in a magnetic field. The presence of a sufficiently strong magnetic field changes the ratio of prot ons to neutrons as well as the neutron drip density. We also study the appearance of muons as well as pion condensa tion in strong magnetic fields. We discuss the possibility that boson condensation in the interior of magn etars is a source of starquakes. Subject headings: stars: interiors — stars: magnetic fields — stars: neutron

Bulletin of the American Physical Society, 2018

The core-cusp problem remains as a challenging discrepancy between observations and simulations i... more The core-cusp problem remains as a challenging discrepancy between observations and simulations in the standard Lambda\LambdaLambdaCDM model for the formation of galaxies. The problem is that Lambda\LambdaLambdaCDM simulations predict a steep power-law mass density profile at the center of galactic dark matter halos. However, observations of dwarf galaxies in the Local Group reveal a density profile consistent with a nearly flat distribution of dark matter near the center. A number of solutions to this dilemma have been proposed. Here, we summarize investigations into the possibility that the dark matter particles themselves self interact and scatter. Such self-interacting dark matter (SIDM) particles can smooth out the dark-matter profile in high-density regions. We also review the theoretical proposal that self-interacting dark matter may arise as an additional Higgs scalar in the 3-3-1 extension of the standard model. We present new simulations of galaxy formation and evolution for this formulation ...

The conversion of neutron matter into strange matter in a neutron star occurs through the non-lep... more The conversion of neutron matter into strange matter in a neutron star occurs through the non-leptonic weak-interaction process. We study the energy loss of the neutron star by the emission of axions in that process. Owing to that process, the neutron star will liberate the energy which can in no way be negligible as an axion burst. PACS numbers : 14.80.Mz, 95.30.Cq, 97.60.Jd

Bulletin of the American Physical Society, 2019

It is anticipated that the gravitational radiation detected in future gravitational wave (GW) det... more It is anticipated that the gravitational radiation detected in future gravitational wave (GW) detectors from binary neutron star (NS) mergers can probe the high density equation of state (EOS). We simulate binary NS mergers which adopt various quark-hadron crossover (QHC) EOSs which are constructed from combinations of a hardronic EOS (n b < 2 n 0) and a quark-matter EOS (n b > 5 n 0), where n b and n 0 are the baryon number density and the nuclear saturation density, respectively. At the crossover densities (2 n 0 < n b < 5 n 0), the QHC EOSs have a gradually increasing stiffness reaching to the stiffness of the strongly correlated quark matter. This enhanced stiffness leads to much longer lifetimes of the hypermassive NS than that for a pure hadronic EOS. We find a dual nature of these EOSs such that their maximum chirp GW frequencies f max fall into the category of a soft EOS while the dominant peak frequencies (f peak) of the postmerger stage falls in between that of a soft and stiff hadronic EOSs. An observation of this kind of dual nature in the characteristic GW frequencies will provide crucial evidence for the existence of strongly interacting quark matter at the crossover densities for QCD.

Progress of Theoretical Physics Supplement - PROG THEOR PHYS SUPPL, 2010

The search for astrophysical evidence for a transition to QCD matter isan important goal. Althoug... more The search for astrophysical evidence for a transition to QCD matter isan important goal. Although much effort has gone into searching for neutron star candidates, here we describe the exploration of two other possible signatures. One is the search for strange dwarfs. Masses and radii for a large number of white dwarfs have been deduced from a combination of proper motion studies, Hipparcos parallax distances, effective temperatures, and binary or spectroscopic masses. Some stars appear to have radii which are significantly smaller than that expected for a standard electron-degenerate white-dwarf equation of state. We argue that there is marginal evidence for bimodality in the radius distribution. We show that the data exhibit several features consistent with the expected mass-radius relation of strange dwarfs. We identify eight nearby white dwarfs that are possible candidates for strange matter cores and suggest observational tests of this hypothesis. We also review the current sta...

Journal of Physics G: …, 2006

Cornell University - arXiv, Oct 29, 2022

The Poisson equation has many applications across the broad areas of science and engineering. Mos... more The Poisson equation has many applications across the broad areas of science and engineering. Most quantum algorithms for the Poisson solver presented so far either suffer from lack of accuracy and/or are limited to very small sizes of the problem, and thus have no practical usage. Here we present an advanced quantum algorithm for solving the Poisson equation with high accuracy and dynamically tunable problem size. After converting the Poisson equation to a linear system through the finite difference method, we adopt the HHL algorithm as the basic framework. Particularly, in this work we present an advanced circuit that ensures the accuracy of the solution by implementing non-truncated eigenvalues through eigenvalue amplification, as well as by increasing the accuracy of the controlled rotation angular coefficients, which are the critical factors in the HHL algorithm. Consequently, we are able to drastically reduce the relative error in the solution while achieving higher success probability as the amplification level is increased. We show that our algorithm not only increases the accuracy of the solutions but also composes more practical and scalable circuits by dynamically controlling problem size in NISQ devices. We present both simulated and experimental results and discuss the sources of errors. Finally, we conclude that though overall results on the existing NISQ hardware are dominated by the error in the CNOT gates, this work opens a path to realizing a multidimensional Poisson solver on near-term quantum hardware.

Cornell University - arXiv, Sep 19, 2022

The Poisson equation has many applications across the broad areas of science and engineering. Mos... more The Poisson equation has many applications across the broad areas of science and engineering. Most quantum algorithms for the Poisson solver presented so far, either suffer from lack of accuracy and/or are limited to very small sizes of the problem, and thus have no practical usage. Here we present an advanced quantum algorithm for solving the Poisson equation with high accuracy and dynamically tunable problem size. After converting the Poisson equation to the linear systems through the finite difference method, we adopt the Harrow-Hassidim-Lloyd (HHL) algorithm as the basic framework. Particularly, in this work we present an advanced circuit that ensures the accuracy of the solution by implementing non-truncated eigenvalues through eigenvalue amplification as well as by increasing the accuracy of the controlled rotation angular coefficients, which are the critical factors in the HHL algorithm. We show that our algorithm not only increases the accuracy of the solutions, but also composes more practical and scalable circuits by dynamically controlling problem size in the NISQ devices. We present both simulated and experimental solutions, and conclude that overall results on the quantum hardware are dominated by the error in the CNOT gates.

American Astronomical Society Meeting Abstracts, Jun 1, 2013

Bulletin of the American Physical Society, Apr 20, 2021

The Astrophysical Journal, 2022

The nuclear equation of state (EOS) is an important component in the evolution of core-collapse s... more The nuclear equation of state (EOS) is an important component in the evolution of core-collapse supernovae. In this paper we make a survey of various EOSs in the literature and analyze their effect on spherical core-collapse models in which the effects of three-dimensional turbulence is modeled by a general relativistic formulation of Supernova Turbulence In Reduced-dimensionality (STIR). We show that the viability of the explosion is quite EOS dependent and that it best correlates with the early-time interior entropy density of the proto–neutron star. We check that this result is not progenitor dependent, although the lowest-mass progenitors show different explosion properties, due to the different pre-collapse nuclear composition. Larger central entropies also induce more vigorous proto–neutron star convection in our one-dimensional turbulence model, as well as a wider convective layer.

The Eleventh Marcel Grossmann Meeting - On Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relativistic Field Theories - Proceedings of the MG11 Meeting on General Relativity, 2008

We summarize masses and radii for a number of white dwarfs as deduced from a combination of prope... more We summarize masses and radii for a number of white dwarfs as deduced from a combination of proper motion studies, Hipparcos parallax distances, effective temperatures, and binary or spectroscopic masses. A puzzling feature of these data, however, is that some stars appear to have radii which are significantly smaller than that expected for a standard electron-degenerate white-dwarf equations of state.

2022 IEEE International Conference on Quantum Computing and Engineering (QCE)

The Fifteenth Marcel Grossmann Meeting

The first detection of gravitational waves a binary neutron star merger GW170817 by the LIGO-Virg... more The first detection of gravitational waves a binary neutron star merger GW170817 by the LIGO-Virgo Collaboration has provided fundamental new insights into the astrophysical site for the r process nucleosynthesis and on the nature of dense neutron-star matter. The detected gravitational wave signal depends upon the tidal distortion of the neutron stars as they approach merger. We examine how the detected "chirp" depends the adopted equation of state. This places new constrains on the properties of nuclear matter. The detected evidence of heavy-element nucleosynthesis also provides insight into the nature of the r-process and the fission properties of the heaviest nuclei. Parametrically, one can divide models for the r-process into three scenarios roughly characterized by the number of neutron captures per seed nucleus (n/s). In addition to neutron-star mergers, these include magneto-hydrodynamic jets from supernovae and the neutrino heated wind above the proto neutron star in core-collapse supernovae. Insight from GW170817 allows one to better quantify the relative contributions of each astrophysical site and the fission termination of the r-process.

EPJ Web of Conferences, 2022

With observations of gravitational wave signals from binary neutron star mergers (BNSM) by LIGO-V... more With observations of gravitational wave signals from binary neutron star mergers (BNSM) by LIGO-Virgo-KAGRA (LVK) Collaboration and NICER, the nuclear equation of state (EOS) is becoming increasingly testable by complementary numerical simulations. Numerous simulations currently explore the EOS at different density regimes for the constituent neutron stars specifically narrowing the uncertainty in the sub-nuclear densities. In this paper we summarize the three-dimensional general relativistic-hydrodynamics based simulations of BNSMs for EOSs with a specific emphasis on the quark matter EOS at the highest densities.

arXiv: General Relativity and Quantum Cosmology, 2016

We study the general relativistic hydrodynamic evolution of neutron stars in binary orbits and an... more We study the general relativistic hydrodynamic evolution of neutron stars in binary orbits and analyze the equation of state dependence of the orbits as the stars approach the inner most last stable circular orbit. We show that by employing a conformally flat condition on the metric, one can stably numerically evolve ~100 quasi-circular orbits and could straightforwardly extend the calculation to the ~10,000 orbits needed to follow stars through the LIGO frequency band. We apply this code to orbiting neutron stars in the quasi-circular orbit approximation to both demonstrate the stability of this approach and explore the equation of state dependence of the orbital properties. We employ variety of available realistic neutron star equations of state as well as a Gamma=2 polytrope. We confirm that both the orbital and emergent gravity wave frequency evolve more slowly for a softer equation of state as the stars approach the innermost stable circular orbit.

Recently, neutron stars with very strong surface magnetic fi lds have been suggested as the site ... more Recently, neutron stars with very strong surface magnetic fi lds have been suggested as the site for the origin of observed soft gamma repeaters (SGRs). In this paper we inv est gate the influence of such strong magnetic fields on the properties and internal structure of these magn etized neutron stars (magnetars). We study properties of a degenerate equilibrium ideal neutron-proton-electro n (npe) gas model in a magnetic field. The presence of a sufficiently strong magnetic field changes the ratio of prot ons to neutrons as well as the neutron drip density. We also study the appearance of muons as well as pion condensa tion in strong magnetic fields. We discuss the possibility that boson condensation in the interior of magn etars is a source of starquakes. Subject headings: stars: interiors — stars: magnetic fields — stars: neutron

Bulletin of the American Physical Society, 2018

The core-cusp problem remains as a challenging discrepancy between observations and simulations i... more The core-cusp problem remains as a challenging discrepancy between observations and simulations in the standard Lambda\LambdaLambdaCDM model for the formation of galaxies. The problem is that Lambda\LambdaLambdaCDM simulations predict a steep power-law mass density profile at the center of galactic dark matter halos. However, observations of dwarf galaxies in the Local Group reveal a density profile consistent with a nearly flat distribution of dark matter near the center. A number of solutions to this dilemma have been proposed. Here, we summarize investigations into the possibility that the dark matter particles themselves self interact and scatter. Such self-interacting dark matter (SIDM) particles can smooth out the dark-matter profile in high-density regions. We also review the theoretical proposal that self-interacting dark matter may arise as an additional Higgs scalar in the 3-3-1 extension of the standard model. We present new simulations of galaxy formation and evolution for this formulation ...

The conversion of neutron matter into strange matter in a neutron star occurs through the non-lep... more The conversion of neutron matter into strange matter in a neutron star occurs through the non-leptonic weak-interaction process. We study the energy loss of the neutron star by the emission of axions in that process. Owing to that process, the neutron star will liberate the energy which can in no way be negligible as an axion burst. PACS numbers : 14.80.Mz, 95.30.Cq, 97.60.Jd

Bulletin of the American Physical Society, 2019

It is anticipated that the gravitational radiation detected in future gravitational wave (GW) det... more It is anticipated that the gravitational radiation detected in future gravitational wave (GW) detectors from binary neutron star (NS) mergers can probe the high density equation of state (EOS). We simulate binary NS mergers which adopt various quark-hadron crossover (QHC) EOSs which are constructed from combinations of a hardronic EOS (n b < 2 n 0) and a quark-matter EOS (n b > 5 n 0), where n b and n 0 are the baryon number density and the nuclear saturation density, respectively. At the crossover densities (2 n 0 < n b < 5 n 0), the QHC EOSs have a gradually increasing stiffness reaching to the stiffness of the strongly correlated quark matter. This enhanced stiffness leads to much longer lifetimes of the hypermassive NS than that for a pure hadronic EOS. We find a dual nature of these EOSs such that their maximum chirp GW frequencies f max fall into the category of a soft EOS while the dominant peak frequencies (f peak) of the postmerger stage falls in between that of a soft and stiff hadronic EOSs. An observation of this kind of dual nature in the characteristic GW frequencies will provide crucial evidence for the existence of strongly interacting quark matter at the crossover densities for QCD.

Progress of Theoretical Physics Supplement - PROG THEOR PHYS SUPPL, 2010

The search for astrophysical evidence for a transition to QCD matter isan important goal. Althoug... more The search for astrophysical evidence for a transition to QCD matter isan important goal. Although much effort has gone into searching for neutron star candidates, here we describe the exploration of two other possible signatures. One is the search for strange dwarfs. Masses and radii for a large number of white dwarfs have been deduced from a combination of proper motion studies, Hipparcos parallax distances, effective temperatures, and binary or spectroscopic masses. Some stars appear to have radii which are significantly smaller than that expected for a standard electron-degenerate white-dwarf equation of state. We argue that there is marginal evidence for bimodality in the radius distribution. We show that the data exhibit several features consistent with the expected mass-radius relation of strange dwarfs. We identify eight nearby white dwarfs that are possible candidates for strange matter cores and suggest observational tests of this hypothesis. We also review the current sta...

Journal of Physics G: …, 2006