231 research outputs found
2017 Ceperley Blue Waters Professor Report
No full text2017 annual report for David Ceperley Blue Waters Professor allocation.Open Restriction set for Item 116674 on 2020-12-02T15:27:14Z with date null by [email protected] by Susan Vinson ([email protected]) on 2020-12-02T15:31:52Z
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Annual-report-BW Ceperley.2017.pdf: 354886 bytes, checksum: b41bf06904c42b9c9ce3d7ce29ad0495 (MD5)
Previous issue date: 2017NSF OCI-0725070NSF ACI-1238993Ope
2016 Ceperley Blue Waters Professor Report
No full text2016 annual report for David Ceperley Blue Waters Professor allocation.Open Restriction set for Item 116669 on 2020-12-01T22:24:25Z with date null by [email protected] by Susan Vinson ([email protected]) on 2020-12-01T22:27:51Z
No. of bitstreams: 1
Annual-report-BW Ceperley (1)_2016.pdf: 181850 bytes, checksum: 1942e5ee965585f49bcf975bbbd995d3 (MD5)Made available in DSpace on 2020-12-01T22:27:51Z (GMT). No. of bitstreams: 1
Annual-report-BW Ceperley (1)_2016.pdf: 181850 bytes, checksum: 1942e5ee965585f49bcf975bbbd995d3 (MD5)
Previous issue date: 2016-01NSF OCI-0725070NSF ACI-1238993Ope
2018 Ceperley Blue Waters Professor Annual Report
No full text2018 annual report for David Ceperley's Blue Waters Professor allocation.Open Restriction set for Item 116597 on 2020-11-12T18:06:26Z with date null by [email protected] by Cynthia Grigorescu ([email protected]) on 2020-11-12T18:13:44Z
No. of bitstreams: 1
Annual-report-BW Ceperley.2018.pdf: 434932 bytes, checksum: 4bfe55d1ade0c365fcb8cd597b551f84 (MD5)Made available in DSpace on 2020-11-12T18:13:44Z (GMT). No. of bitstreams: 1
Annual-report-BW Ceperley.2018.pdf: 434932 bytes, checksum: 4bfe55d1ade0c365fcb8cd597b551f84 (MD5)
Previous issue date: 2018-01NSF OCI-0725070NSF ACI-1238993Ope
2019 Ceperley Blue Waters Professor Report
No full textOpenNSF ACI-12389932019 annual report for David Ceperley Blue Waters Professor allocation.Open Restriction set for Item 116675 on 2020-12-02T15:41:08Z with date null by [email protected] by Susan Vinson ([email protected]) on 2020-12-02T15:45:06Z
No. of bitstreams: 1
Annual-report-BW Ceperley.Dec2019.pdf: 363172 bytes, checksum: 915f94ff0105a07085ad14147d959163 (MD5)Made available in DSpace on 2020-12-02T15:45:06Z (GMT). No. of bitstreams: 1
Annual-report-BW Ceperley.Dec2019.pdf: 363172 bytes, checksum: 915f94ff0105a07085ad14147d959163 (MD5)
Previous issue date: 2019-12NSF OCI-072507
2015 Ceperley Blue Waters Professor Report
No full text2015 annual report for David Ceperley Blue Waters Professor allocation.Open Restriction set for Item 116667 on 2020-12-01T22:17:45Z with date null by [email protected] by Susan Vinson ([email protected]) on 2020-12-01T22:21:33Z
No. of bitstreams: 1
Annual-report-BW Ceperley_2015.pdf: 118013 bytes, checksum: c1bf88f5be8022fb5bca610dfa573380 (MD5)Made available in DSpace on 2020-12-01T22:21:33Z (GMT). No. of bitstreams: 1
Annual-report-BW Ceperley_2015.pdf: 118013 bytes, checksum: c1bf88f5be8022fb5bca610dfa573380 (MD5)
Previous issue date: 2015NSF OCI-0725070NSF ACI-1238993Ope
Benchmarking vdW‐DF first‐principles predictions against Coupled Electron–Ion Monte Carlo for high‐pressure liquid hydrogen
No full textWe report first-principles results for the nuclear structure and optical responses of high-pressure liquid hydrogen along two isotherms in the region of molecular dissociation. We employ density functional theory with the vdW-DF approximation (vdW) and benchmark the results against existing predictions from Coupled Electron–Ion Monte Carlo (CEIMC). At fixed density and temperature, we find that the pressure obtained from vdW is higher than that from CEIMC by about 10 GPa in the molecular insulating phase and about 20 GPa in the dissociated metallic phase. Molecules are found to be over-stabilized using vdW, with a slightly shorter bond length and with a stronger resistance to compression. As a consequence, pressure dissociation along isotherms using vdW is more progressive than that computed with CEIMC. Below the critical point, the liquid–liquid phase transition is observed with both theories in the same density region, but the one predicted by vdW has a smaller density discontinuity, i.e. a smaller first-order character. The optical conductivity computed using Kubo–Greenwood formulation is rather similar for the two systems and reflects the slightly more pronounced molecular character of vdW
Optical properties of high-pressure fluid hydrogen across molecular dissociation
No full textOptical properties of compressed fluid hydrogen in the region where dissociation and metallization is observed are computed by ab initio methods and compared with recent experimen- tal results. We confirm that at T>3,000 K, both processes are continuous, while at T<1,500 K, the first-order phase transi- tion is accompanied by a discontinuity of the dc conductivity and the thermal conductivity, while both the reflectivity and absorption coefficient vary rapidly but continuously. Our results support the recent analysis of National Ignition Facility (NIF) experiments [Celliers PM, et al. (2018) Science 361:677–682], which assigned the inception of metallization to pressures where the reflectivity is ⇠0.3. Our results also support the conclusion that the temperature plateau seen in laser-heated diamond-anvil cell (DAC) experiments at temperatures higher than 1,500 K corre- sponds to the onset of optical absorption, not to the phase transition. hydroge
The early years of quantum Monte Carlo (1): the ground state
No full textThe history of the development of Monte Carlo methods to solve the many-body problem in quantum mechanics is presented. The relation starts with the early attempts on first available computers just after the war and extends until the years 80s with the celebrated calculation of the electron gas by Ceperley and Alder. Usage is made of an interview of David Ceperley by the author
Pairing and entanglement: quantum Monte Carlo studies
No full textDescribed in this dissertation is the use of quantum Monte Carlo methods to study two ideas in quantum many-body problems: superfluidity and entanglement. Density matrices are presented a central tool in the analysis, as are discussed in the review of path integral Monte Carlo (PIMC) and variational Monte Carlo (VMC) methods. PIMC is used to model a one-dimensional system of fermionic lithium atoms according to existing experiments, including a realistic temperature. New estimators of the pair momentum distribution are implemented, yielding in a clear in-situ signature of a pairing mechanism (dubbed FFLO after its first proposers) which implies a microscopic phase fluctuation in space between a normal fluid and a superfluid. VMC is used to model homonuclear diatomic molecules of period-2 elements. The degree of entanglement and the responsible electronic configurations in real space are quantified in terms of the entanglement spectra. Calculating the reduced denstity matrix as an intermediate step reveals a novel way of understanding chemical bonds, as exemplified by Be2 and C2 . Possible implications of these results in integrable many-body models and in quantum chemistry are discussed, as well as direction for future investigation.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-05-01The student, David Yang, accepted the attached license on 2016-04-05 at 03:00.The student, David Yang, submitted this Dissertation for approval on 2016-04-05 at 03:12.This Dissertation was approved for publication on 2016-04-07 at 13:32.DSpace SAF Submission Ingestion Package generated from Vireo submission #9148 on 2016-07-07 at 13:48:51Made available in DSpace on 2016-07-07T20:27:06Z (GMT). No. of bitstreams: 3
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Previous issue date: 2016-04-07Embargo set by: Seth Robbins for item 93089
Lift date: 2018-07-07T20:28:14Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 93089
Lift date: 2018-07-07T20:35:34Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 93089 on 2018-07-08T09:15:23Z
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