Efficient symmetry-preserving state preparation circuits for the variational quantum eigensolver algorithm
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Conclusions from Bidirectional Reflectance Distribution Function (BRDF) Measurements: Mirrors are specular and have consistent reflectance over a range of angles. The measured power of the reflected light was consistent for all power meter positions; Kapton had a similar specular response as the mirror (FWHM), but displayed varying power levels for the different power meter positions (much like the Anodized AI and the Solar Cells); The Solar Cells had very high loss consistent with a material that is supposed to absorb light, but still exhibited specular behavior for FWHM; The Anodized AI had the most diffuse (highest FWHM) reflectance and low BRDF amplitude; Also tried to measure the BRDF Aeroglaze (a common satellite coating) but the power meter was not sensitive enough. To the eye, this material seemed very absorbent and any reflection would be very diffuse.
The Field Office has a cultural resources program manager. The LANL Management and Operating Contractor has a staff of cultural resource specialists who meet the qualifications set forth in the Secretary of the Interior's Standards and Guidelines for Professional Qualifications (36 CFR Part 61), or work under the supervision of individuals who meet these qualifications. Any future Management and Operating Contractor will have a staff of Secretary of the Interior-qualified cultural resource specialists.
Abstract Decoherence-free subspaces and subsystems (DFS) preserve quantum information by encoding it into symmetry-protected states unaffected by decoherence. An inherent DFS of a given experimental system may not exist; however, through the use of dynamical decoupling (DD), one can induce symmetries that support DFSs. Here, we provide the first experimental demonstration of DD-generated decoherence-free subsystem logical qubits. Utilizing IBM Quantum superconducting processors, we investigate two and three-qubit DFS codes comprising up to six and seven noninteracting logical qubits, respectively. Through a combination of DD and error detection, we show that DFS logical qubits can achieve up to a 23% improvement in state preservation fidelity over physical qubits subject to DD alone. This constitutes a beyond-breakeven fidelity improvement for DFS-encoded qubits. Our results showcase the potential utility of DFS codes as a pathway toward enhanced computational accuracy via logical encoding on quantum processors.
The magnetic order for several compositions of CaK(Fe$_{1-x}$Mn$_x$) 4 As 4 has been studied by nuclear magnetic resonance (NMR), Mössbauer spectroscopy, and neutron diffraction. Our observations for the Mn-doped 1144 compound are consistent with the hedgehog spin vortex crystal (hSVC) order which has previously been found for Ni-doped CaKFe 4 As 4 . The hSVC state is characterized by the stripe-type propagation vectors $(\pi\,0)$ and $(0\,\pi)$ just as in the doped 122 compounds. The hSVC state preserves tetragonal symmetry at the Fe site, and only this SVC motif with simple antiferromagnetic (AFM) stacking along $\ c$ is consistent with all our observations using NMR Mössbauer spectroscopy, and neutron diffraction. We find that the hSVC state in the Mn-doped 1144 compound coexists with superconductivity (SC), and by combining the neutron scattering and Mössbauer spectroscopy data we can infer a quantum phase transition, hidden under the superconducting dome, associated with the suppression of the AFM transition temperature ($T_N$) to zero for $x$ ≈ 0.01. In addition, unlike several 122 compounds and Ni-doped 1144, the ordered magnetic moment is not observed to decrease at temperatures below the superconducting transition temperature ($T_c$).
In this article, we examine how the structure of system–bath interactions can determine commonly encountered temporal decoherence patterns, such as Gaussian and exponential decay, in molecular and other qubits coupled to a thermal bosonic bath. The analysis, based on a pure dephasing picture that admits analytical treatment, shows that decoherence, in general, is neither purely Gaussian nor exponential but rather the exponential of oscillatory functions, with periods determined by the bath’s frequencies. For initially unentangled qubit-bath states, Gaussian decay is always present at early times. It becomes increasingly dominant with increasing temperature, qubit–bath interaction strength, and bath correlation time. Initial system–bath entanglement that arises due to displacement in the position of the bath states preserves the Gaussian decay. By contrast, strict exponential decay arises only in very specific models that we isolate. However, it becomes dominant for times longer than the bath correlation time or for early times when there is initial entanglement due to momentum displacement of the bath states. For molecular electronic decoherence, the long-time exponential regime plays a limited role as it emerges after most coherence is lost. Thus, the Gaussian decay provides a more suitable (albeit imperfect) model of such decoherence. Furthermore, we discuss the connection between electronic decoherence dynamics and electronic spectroscopic line shape theory, where Gaussian spectral peaks correspond to Gaussian coherence decay and Lorentzian peaks correspond to exponential coherence decay. We find that Gaussian spectral peaks, usually associated with inhomogeneous broadening, can emerge from the entangling unitary system–bath dynamics even when there is no inhomogeneity in the initial conditions.
First-principles statistical mechanics enables the prediction of thermodynamic and kinetic properties of materials, but is computationally expensive. Many approaches require surrogate models to calculate energies within Monte Carlo or molecular dynamics simulations. Inexpensive surrogates such as cluster expansions enable otherwise intractable calculations by interpolating data from higher accuracy methods, such as Density Functional Theory (DFT). Surrogate models introduce uncertainty into downstream calculations, in addition to any uncertainty inherent to DFT calculations. Bayesian frameworks address this by quantifying uncertainty and incorporating expert knowledge through priors. However, constructing effective priors remains challenging. This work introduces and describes practical strategies for building Bayesian cluster expansions, focusing on basis truncation, hyperparameter selection, and ground state replication. We analyze multiple basis truncation schemes, compare cross-validation to the evidence-approximation for hyperparameter optimization, and provide methods to find and enforce ground-state-preserving models through priors. Additionally, we compare the uncertainties between different approximations to DFT (LDA, PBE, SCAN) against the uncertainty introduced with the use of cluster expansion surrogate models. These approaches are demonstrated on the BCC Li x Mg 1-x and Li x Al 1-x alloys, which are both of interest for solid-state Li batteries. Our results provide guidelines for constructing and utilizing Bayesian cluster expansions, thereby improving the transparency of materials modeling. Furthermore, the approaches and insights developed in this work can be transferred to a wide range of cluster expansion surrogate models, including the atomic cluster expansion and related machine-learned interatomic potential architectures.
Loess-paleosol sequences in eolian deposits on the Snake River Plain, Idaho, western United States, preserve records of late Pleistocene to Holocene glacial-interglacial cycles. Here, we examine climate-driven changes in the timing and rate of loess accretion, soil formation, and pedogenic carbonate accumulation in the eastern and central Snake River Plain. High rates of loess deposition often correspond with dry, cold, and windy conditions and/or high sediment supply, while soil formation indicates landscape stability. Optically stimulated luminescence dating of four loess-soil sequences provides a record of the timing of loess deposition, and radiocarbon dating ( 14 C) of soil inorganic carbon provides ages for soil formation and pedogenic carbonate precipitation. On the central Snake River Plain, marine isotope stage (MIS) 3 is marked by loess deposition between ca. 50 ka and 33 ka, and pedogenic carbonate accumulation between ca. 42 ka calibrated years before present (cal. B.P.) and 31 ka cal. B.P. During MIS 2, loess deposition between ca. 21 ka and 15 ka is contemporaneous with pedogenic carbonate precipitation. MIS 2 is characterized by diffuse pedogenic carbonate formation and rapid loess accumulation. Both the eastern and central Snake River Plain study sites experienced high rates of loess deposition during MIS 2; however, the eastern Snake River Plain had almost three times faster rates of loess accumulation (0.56−0.63 m/k.y. from ca. 25 ka to 17 ka) as compared to the central Snake River Plain (0.18−0.26 m/k.y. from ca. 21 ka to 15 ka). During MIS 1, loess deposition on the central Snake River Plain ca. 11 ka was coincident with pedogenic carbonate formation ca. 10 ka cal. B.P. MIS 3 and MIS 1 are characterized by A horizons and well-developed Bk horizons, indicating soil stability and lower rates of loess accumulation during these intervals. Finally, this study highlights the role of late Quaternary−scale climatic variability on rates and amounts of soil inorganic carbon storage.
The Shifted Boundary Method (SBM) belongs to the class of unfitted (or immersed, or embedded) finite element methods, and relies on reformulating the original boundary value problem over a surrogate (approximate) computational domain. The surrogate domain is constructed so as to avoid cut cells and the associated problematic implementation and numerical integration issues. Accuracy is maintained by modifying the original boundary conditions using Taylor expansions: hence the name of the method, that shifts the location and values of the boundary conditions. Here, in this article, we extend the SBM to the simulation of incompressible Stokes flow, by appropriately weighting its variational form with the elemental volume fraction of active fluid. This approach allows to drastically reduce spurious pressure oscillations in time, which are produced if the total volume of active fluid were to change abruptly over a time step. The proposed Weighted SBM (W-SBM) exactly preserves states of hydrostatic equilibrium, and induces small mass and momentum conservation errors, which converge as the grid is refined. This is in analogy to cutFEMs and related unfitted approaches, which rely on an affine representation of cut boundaries. We demonstrate the robustness and accuracy of the proposed method with an extensive suite of two-dimensional tests.
Summary Associated with the Milne Point polymer flood (on Alaska’s North Slope), this paper explores the unusual shape of hydrolyzed polyacrylamides (HPAM) breakout/propagation during dynamic polymer retention measurements in Milne Point core material. In contrast to conventional expectations, polymer retention does not delay the initial polymer arrival at the end of a Milne Point core. However, after effluent polymer concentrations rapidly rise to at least 50% of the injected value, the concentration gradually “tails” up over many pore volumes (PVs) before it finally achieves the injected value. To understand the origin and significance of this behavior, a wide range of core experiments were performed, including substantial variations in polymer concentration and molecular weight, core length, preservation state, sand grain size, and mineral composition. Illite was identified as primarily responsible for the tailing phenomenon. This phenomenon has important consequences that must be considered when projecting the performance of the field project. This work suggests that mineralogy analysis (especially for illite and kaolinite) may reveal whether tailing should be accounted for during simulations of polymer propagation/retention in a given field application.
The QICK (Quantum Instrumentation Control Kit) integration aims to enhance the readout of superconducting qubits by leveraging machine learning (ML) techniques. These techniques offer high accuracy, increased speed, and better state preservation for qubit readouts. The integration process employs neural network algorithms to optimize system performance and achieve high accuracy rates. The QICK board uses an FPGA, allowing for efficient real-time processing and high-performance execution of machine learning algorithms.
Neutral atoms are a promising platform for quantum science, enabling advances in areas ranging from quantum simulations and computation to metrology, atomic clocks and quantum networking. Although atom losses typically limit these systems to a pulsed mode, continuous operation could substantially enhance cycle rates, remove bottlenecks in metrology and enable deep-circuit quantum evolution through quantum error correction. Here we demonstrate an experimental architecture for high-rate reloading and continuous operation of a large-scale atom-array system while realizing coherent storage and manipulation of quantum information. Our approach utilizes a series of two optical lattice conveyor belts to transport atom reservoirs into the science region, where atoms are repeatedly extracted into optical tweezers without affecting the coherence of qubits stored nearby. Using a reloading rate of 300,000 atoms in tweezers per second, we create over 30,000 initialized qubits per second, which we leverage to assemble and maintain an array of over 3,000 atoms for more than 2 hours. Furthermore, we demonstrate persistent refilling of the array with atomic qubits in either a spin-polarized or a coherent superposition state while preserving the quantum state of stored qubits. Our results pave the way for the realization of large-scale continuously operated atomic clocks, sensors and fault-tolerant quantum computers.
The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office (NNSA/NFO) plans to install a 26.45-mile-long 138-kilovolt (kV) transmission line on the Nevada National Security Site (NNSS) in Nye County, Nevada. This new transmission line will upgrade the electrical transmission system and provide reliable power between Mercury Switching Station in Area 23 and the U1a Facility in Area 1. The proposed upgrade to the power transmission system constitutes an undertaking subject to review under Section 106 of the National Historic Preservation Act (NHPA) (54 United States Code [USC] § 306101) and its implementing regulations, 36 Code of Federal Regulations (CFR) Part 800. A portion of this new transmission line will cross the western perimeter of the Reynolds Electrical and Engineering Company (REECo) Maintenance Compound located in Area 6 of the NNSS. This compound with its trade shops, storage sheds, and yards served as a general construction facility that supported nuclear testing activities on the NNSS from 1967 to 1992. Although three architectural resources in the compound have previously been recorded and evaluated for the National Register of Historic Places (NRHP), other resources within it have not, nor has the compound been recorded and evaluated as a potential district. The State Historic Preservation Officer (SHPO) concurred with NNSA/NFO’s determination that the unevaluated REECo Maintenance Compound will be adversely affected by the proposed undertaking (Reed 2021). The NNSA/NFO, in consultation with the SHPO, then developed the Memorandum of Agreement DE-GM58-22NA25553 between the U.S. Department of Energy and the Nevada State Historic Preservation Officer Regarding Installation of a 138-kilovolt Transmission Line from the Mercury Switching Station to the U1a Facility and the Removal of the Historic 138-kilovolt Transmission Line from the Mercury Switching Station to the U1a Facility in Areas 1, 3, 5, 6, and 23 of the Nevada National Security Site, Nye County, hereafter referred to as the MOA. This architectural survey report was prepared in accordance with MOA Stipulation III.B. It describes the origins, history, layout, and functions of the REECo Maintenance Compound during the Cold War and identifies contributing and noncontributing resources. The report defines a district boundary based on archival research and the field survey and concludes with an appendix that presents digital color images of the compound with descriptions and a map key showing image viewpoints and directions. Although none of the architectural resources are recommended individually eligible, the district evaluation concludes the REECo Maintenance Compound is eligible as a historic district for listing in the NRHP under the Secretary of the Interior’s Significance Criteria A and C at the local level. The historic district retains all seven aspects of integrity and conveys its significance under the abovementioned criteria.
The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office (NNSA/NFO) proposes to demolish five buildings and five accessory resources in the Area 6 Control Point at the Nevada National Security Site (NNSS) in Nye County, Nevada. The demolition and removal of the buildings and accessories constitute an undertaking subject to review under Section 106 of the National Historic Preservation Act (NHPA) (54 United States Code [USC] § 306101) and its implementing regulations, 36 Code of Federal Regulations (CFR) Part 800. The buildings and accessories were recorded in Identification and Evaluation of 14 Architectural Resources Scheduled for Demolition, Area 6 Control Point and Vicinity, Nevada National Security Site, Nye County, Nevada (Menocal et al. 2020). The report found that the five buildings were not individually eligible for listing in the National Register of Historic Places (NRHP, National Register) but were potentially eligible as contributing elements to an unrecorded Area 6 Control Point district. The report also found that the five accessory resources were not individually eligible for the NRHP but they contributed to other historic properties, including the contributing elements to the unrecorded district. Finally, the report found that the undertaking would result in an adverse effect to historic properties. The State Historic Preservation Office (SHPO) concurred with the report’s findings regarding the eligibility of the buildings and structures in the Area of Potential Effect (APE) and that the undertaking would result in an adverse effect (Reed 2020). The NNSA/NFO, in consultation with the SHPO, then developed the Memorandum of Agreement DE-GM58-21NA25543 Between the U.S. Department of Energy and the Nevada State Historic Preservation Officer Regarding Demolition of Fourteen Buildings and Structures in Area 6 of the Nevada National Security Site, Nye County, hereafter referred to as the MOA. The MOA stipulates that a district boundary be delineated with an accompanying boundary report and supporting photographs (Stipulation III.A) followed by an architectural survey of the potential historic district (Stipulation III.B). The SHPO reviewed and concurred with the proposed district boundary and accompanying boundary report and photographs (O’Neill et al. 2021) on August 23, 2021, in fulfillment of Stipulation III.A (Reed 2021). This architectural survey report has been prepared in accordance with Stipulation III.B. It includes an NRHP evaluation of the district, identifies contributing and non-contributing elements, and is accompanied by Architectural Resource Assessment (ARA) forms. The NRHP evaluation concludes that the Area 6 Control Point is recommended eligible as a historic district under the Secretary of the Interior’s Significance Criterion A at the national level as the location of the command center and various support facilities directly related to timing and firing operations for nuclear testing on the NNSS from 1951 to 1992. It is also recommended eligible under Significance Criterion C for embodying the distinctive characteristics of a nuclear command center in the context of the Cold War and as a significant and distinguishable entity. There are a total of 29 primary resources within the district boundary. Of these, 28 are recommended as contributing elements to the Area 6 Control Point Historic District and one is recommended as non-contributing.
The U.S. Department of Energy (DOE), in conjunction with the National Nuclear Security Administration Nevada Field Office (NNSA/NFO), proposes to demolish six buildings and three storage areas located at the U12g Tunnel portal area in Area 12 of the Nevada National Security Site (NNSS). The buildings are 12-358 (Signal Vault); 12-201800 (Storage Quonset Hut); 12-202555 (Walker Shack); 12-868 (Pipe Assembly); 12-B100933 (Electrical Shop); 12-B100944 (Conference Room); and Storage Area 1; Storage Area 2; and Storage Area 3. The buildings and storage areas were selected for demolition as part of the DOE’s Real Property Efficiency Plan to reduce the footprint of unused and non-operational facilities on the NNSS. They are all vacant and have no proposed uses for current or upcoming NNSS missions. Demolition activities constitute an undertaking subject to review under Section 106 of the National Historic Preservation Act (NHPA) (54 United States Code [USC] § 306101) and its implementing regulations, 36 Code of Federal Regulations (CFR) Part 800. Identification efforts began with resources proposed for demolition in federal Fiscal Year (FY) 23. Four buildings were proposed to be demolished in FY23 (12-358, 12-868, 12-201800, and 12-202555). These buildings and the U12g Tunnel Historic District (SHPO No. D444) were recorded in Identification, Evaluation, and Finding of Adverse Effect for the Proposed Demolition of Five Buildings in Area 12, Nevada National Security Site, Nye County, Nevada (Menocal et al. 2023). Identification efforts indicated three buildings (12-358, 12-201800, and 12-868) supported nuclear testing in the U12g Tunnel. The fourth building post-dated the use of U12g Tunnel for nuclear testing activities. The report recommended that three of the four buildings (12-358, 12-201800, 12-868) and the U12g Tunnel Historic District may be eligible for the National Register of Historic Places (NRHP). The report also found that the undertaking would have an adverse effect on the three buildings and on the historic district. The Nevada State Historic Preservation Office (SHPO) concurred with the report’s findings (Reed 2023). The U12g Tunnel was determined eligible as a historic district under the Secretary of the Interior’s (SOI) Significance Criterion A, at the local level, in the context of the Cold War as an underground testing environment for the development of nuclear weapons and to assess the effects of a nuclear explosion on materials and equipment with a period of significance from 1959 to 1971. It was also determined eligible under Significance Criterion C for embodying the distinctive characters of a horizontal tunnel complex used for nuclear testing and as a significant and distinguishable entity. The three buildings were determined to be contributing elements of the district. The undertaking was expanded with the addition of two buildings and three storage areas proposed to be demolished and located within U12g Tunnel Historic District in FY24. These five resources (12-B100933, 12-B100944, and Storage Areas 1, 2, and 3) were recorded in Supplemental Identification, Evaluation, and Finding of Effect for Additional Proposed Demolition at U12g Tunnel, Area 12, Nevada national Security Site, Nye County, Nevada (Brannan et al. 2024). Identification efforts indicated that the two buildings and Storage Area 1 supported nuclear testing in the U12g Tunnel. Storage Area 1 and Storage Area 2 post-dated the nuclear testing activities at U12g Tunnel and were not recommended as contributing elements to the district. The report also found that the undertaking would have an adverse effect on the newly identified buildings and one storage area and on the historic district. The SHPO concurred that the expanded undertaking would result in adverse effects to historic properties (Reed 2025). To resolve these adverse effects, NNSA/NFO, in consultation with the SHPO, is following standard mitigation as stipulated in the 2024 Programmatic Agreement DE-GM58-22NA25554 Among the U.S. Department of Energy and the Nevada State Historic Preservation Officer and the Advisory Council on Historic Preservation Concerning the Protection of Historic Properties on the Nevada National Security Site, Nye County, Nevada (hereafter referred to as the NNSS PA). The standard mitigation measures are outlined in Appendix D of the NNSS PA. As such, this architectural survey has been prepared in accordance with Appendix D of the NNSS PA and follows the report format outlined in Appendix F. It includes a historic context that describes the district’s origin, history, and support functions, its significance in the context of nuclear testing on the NNSS, and identifies contributing and non-contributing elements within the district. The report is accompanied by Architectural Resource Assessment (ARA) forms for individual resources and a Historic District Resource Assessment (HDRA) for the U12g Tunnel Historic District. In total, this architectural report identified 32 primary resources within the district boundary. Six of the primary resources were previously identified as contributing elements. An additional 17 resources are recommended as contributing elements to the district for a total of 23 contributing elements. The other nine resources identified are recommended as non-contributing elements to the district.
The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office (NNSA/NFO) plans to demolish Building 23-620 in the town of Mercury (Nevada State Historic Preservation Office [SHPO] Resource No. B15283), which is on the Nevada National Security Site (NNSS) in Nye County, Nevada (see Figure 1). The purpose of the undertaking is related to the modernization of Mercury for future mission needs. The NNSA/NFO will implement this undertaking in accordance with the Programmatic Agreement between the National Nuclear Security Administration Nevada Field Office and the Nevada State Historic Preservation Officer Regarding Modernization and Operational Maintenance of the Nevada National Security Site, at Mercury in Nye County, Nevada, hereafter referred to as the Mercury PA. Building 23-620 was built in 1968 as office space for the Los Alamos Scientific Laboratory (LASL), who worked on the design and engineering of nuclear weapons. In the 1990s, it became a maintenance facility for Reynolds Electrical & Engineering Company (REECo), and eventually, it became the Real Estate Services building in 2004. The town of Mercury and the immediate surrounding area have been formally determined eligible for listing in the National Register of Historic Places (National Register, NRHP) as the Mercury Historic District (MHD, SHPO Resource No. D230) under Criteria A and C for its importance in supporting nuclear testing and scientific research from 1951 through 1992. Building 23-620 was identified as a contributing element to the MHD in a 2018 architectural survey of the district (Reno et al.) and recorded on a Nevada Architectural Resource Assessment (ARA) form (Reno et al. 2017). Building 23-620 was also identified in Appendix C of the Mercury PA as a Category I contributing element, indicating that it might be individually eligible for the NRHP. It is a historic property for the purposes of compliance with Section 106 of the National Historic Preservation Act (NHPA) and subject to the stipulations of the Mercury PA. Mitigation Report: The purpose of this letter report is to submit documentation related to the mitigation of the demolition of Building 23-620 (Nevada State Historic Preservation Office [SHPO] Resource No. B15283) in the Mercury Historic District (MHD, SHPO Resource No. D230). This submission is intended to comply with the stipulations in the Programmatic Agreement between the National Nuclear Security Administration Nevada Field Office and the Nevada State Historic Preservation Officer Regarding Modernization and Operational Maintenance of the Nevada National Security Site, at Mercury in Nye County, Nevada, hereafter referred to as the Mercury PA.
The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office (NNSA/NFO) plans to demolish Building 23-530 in Mercury (Nevada State Historic Preservation Office [SHPO] Resource No. B15270), which is on the Nevada National Security Site (NNSS) in Nye County, Nevada. The purpose of the undertaking is related to the modernization of Mercury for future mission needs. The NNSA/NFO will implement this undertaking in accordance with the Programmatic Agreement Between the National Nuclear Security Administration Nevada Field Office and the Nevada State Historic Preservation Officer Regarding Modernization and Operational Maintenance of the Nevada National Security Site, at Mercury in Nye County, Nevada, hereafter referred to as the Mercury PA. Building 23-530, a dormitory called Freedom Hall, was constructed in Mercury in 1982 and served as a support facility for nuclear testing for the last decade of the Cold War. The town of Mercury and the immediate surrounding area have been determined eligible for listing in the National Register of Historic Places (NRHP) as the Mercury Historic District (MHD, SHPO Resource No. D230) under Criteria A and C for their importance in supporting nuclear testing and scientific research from 1951 through 1992 (Reed 2019). Building 23-530 was identified as a contributing element to the MHD in a 2018 architectural survey of the district (Reno et al. 2018) and recorded on a Nevada Architectural Resource Assessment (ARA) form (Reno et al. 2017). Building 23-530 was also identified in Appendix C of the Mercury PA as a Category II contributing element. Category II properties are those that have several representatives in the MHD but may possess different engineering or architectural characteristics that distinguish them from other classes of similar elements. Building 23-530 is a historic property for the purposes of compliance with Section 106 of the National Historic Preservation Act (NHPA) and subject to the stipulations of the Mercury PA. The purpose of this letter report is to submit documentation related to the mitigation of the demolition of Building 23-530 (Nevada State Historic Preservation Office [SHPO] Resource No. B15270) in the Mercury Historic District (MHD, SHPO Resource No. D230) at the Nevada National Security Site (NNSS) in Nye County, Nevada. The dormitory is considered contributing to the significance of the district both for its historic importance in relation to nuclear testing under Criterion A and as a part of the distinctive design and construction of the district under Criterion C. This submission is intended to comply with the stipulations in the Programmatic Agreement between the National Nuclear Security Administration Nevada Field Office and the Nevada State Historic Preservation Officer Regarding Modernization and Operational Maintenance of the Nevada National Security Site, at Mercury in Nye County, Nevada, hereafter referred to as the Mercury PA.
Finding of Effect: The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office (NNSA/NFO) plans to demolish Building 23-W10 in Mercury (Nevada State Historic Preservation Office [SHPO] Resource No. B15228), which is on the Nevada National Security Site (NNSS) in Nye County, Nevada (Figure 1). The purpose of the undertaking is related to the modernization of Mercury for future mission needs. The NNSA/NFO will implement this undertaking in accordance with the Programmatic Agreement between the National Nuclear Security Administration Nevada Field Office and the Nevada State Historic Preservation Officer Regarding Modernization and Operational Maintenance of the Nevada National Security Site, at Mercury in Nye County, Nevada, hereafter referred to as the Mercury PA. Building 23-W10, a supply warehouse, was installed in Mercury in 1962 (NNSS GIS Database) and served as a support facility for nuclear testing throughout much of the Cold War. It was likely produced during World War II (WWII) and previously installed at Camp Desert Rock. The town of Mercury and the immediate surrounding area have been formally determined eligible for listing in the National Register of Historic Places (National Register, NRHP) as the Mercury Historic District (MHD, SHPO Resource #D230) under Criteria A and C for their importance in supporting nuclear testing and scientific research from 1951 through 1992. Building 23-W10 was identified as a contributing element to the MHD in a 2018 architectural survey of the district (Reno et al. 2018) and recorded on a Nevada Architectural Resource Assessment (ARA) form (Reno et al. 2017). Building 23-W10 was also identified in Appendix C of the Mercury PA as a Category II contributing element. Category II properties are those that have several representatives in the MHD, such as warehouses, but may possess different engineering or architectural characteristics that distinguish them from other classes of similar elements. Building 23-W10 is a historic property for the purposes of compliance with Section 106 of the National Historic Preservation Act (NHPA) and subject to the stipulations of the Mercury PA. Mitigation: The purpose of this letter report is to support the mitigation of the demolition of Building 23-W10 (Nevada State Historic Preservation Office [SHPO] Resource No. B15228) in the Mercury Historic District (MHD, SHPO Resource #D230) at the Nevada National Security Site (NNSS) in Nye County, Nevada. The warehouse is considered contributing to the significance of the district both for its historic importance in relation to nuclear testing under Criterion A and as a part of the distinctive design and construction of the district under Criterion C. This submission is intended to comply with the stipulations in the Programmatic Agreement between the National Nuclear Security Administration Nevada Field Office and the Nevada State Historic Preservation Officer Regarding Modernization and Operational Maintenance of the Nevada National Security Site, at Mercury in Nye County, Nevada, hereafter referred to as the Mercury PA.